WP_Date_Query{}WP 3.7.0AllowDynamicProperties

Class for generating SQL clauses that filter a primary query according to date.

WP_Date_Query is a helper that allows primary query classes, such as WP_Query, to filter their results by date columns, by generating WHERE subclauses to be attached to the primary SQL query string.

Attempting to filter by an invalid date value (eg month=13) will generate SQL that will return no results. In these cases, a _doing_it_wrong() error notice is also thrown. See WP_Date_Query::validate_date_values().

1 time — 0.00050 sec (fast) | 50000 times — 15.4 sec (slow)

Usage

$WP_Date_Query = new WP_Date_Query();
// use class methods

Methods

  1. public __construct( $date_query, $default_column = 'post_date' )
  2. public build_mysql_datetime( $datetime, $default_to_max = false )
  3. public build_time_query( $column, $compare, $hour = null, $minute = null, $second = null )
  4. public build_value( $compare, $value )
  5. public get_compare( $query )
  6. public get_sql()
  7. protected get_sql_clauses()
  8. protected get_sql_for_clause( $query, $parent_query )
  9. protected get_sql_for_query( $query, $depth = 0 )
  10. protected get_sql_for_subquery( $query )
  11. protected is_first_order_clause( $query )
  12. public sanitize_query( $queries, $parent_query = null )
  13. public sanitize_relation( $relation )
  14. public validate_column( $column )
  15. public validate_date_values( $date_query = array() )

Examples

0

#1 Exact dates

Get the SQL request part for the time period from July to September 2013 (inclusive)

$query_args = [
	'relation' => 'AND',
	[ 'year' => 2013, 'month' => 7, 'compare' => '>=' ],
	[ 'year' => 2013, 'month' => 9, 'compare' => '<=' ],
];

$query = new WP_Date_Query( $query_args, 'post_date' );

echo $query->get_sql();

/* Will withdraw:
AND (
 ( YEAR( wp_posts.post_date ) >= 2013 AND MONTH( wp_posts.post_date ) >= 7 )
 AND
 ( YEAR( wp_posts.post_date ) <= 2013 AND MONTH( wp_posts.post_date ) <= 9 )
)
*/
0

#2 Relative dates

Get the query: last 2 weeks relative to the current date:

$query_args = array(
	array('after' => '2 weeks ago'),
	// array('after' => '-2 week'), // or you can write it like this
	// 'after' => '2 weeks ago' // or you can write
)

$query = new WP_Date_Query( $query_args, 'post_date' );

echo $query->get_sql();

// Will lead out:
// AND ( wp_posts.post_date > '2015-05-18 00:51:09' )
0

#3 Posts published before July 1, 2015 on weekdays

This example shows how to create the WHERE part of a SQL query to get all posts published before July 1, 2015 on weekdays (Mon-Fri):

$query_args = array(
	'relation' => 'AND',
	array(
		'dayofweek_iso' => [ 1, 5 ],
		'compare'       => 'BETWEEN',
	),
	array(
		'before' => 'July 1st, 2015'
	),
);

$query = new WP_Date_Query( $query_args, 'post_modified' );

echo $query->get_sql();

/* Will withdraw:
AND (
 WEEKDAY( wp_posts.post_modified ) + 1 BETWEEN 1 AND 5
 AND
 wp_posts.post_modified < '2015-07-01 00:00:00'
)
*/
0

#4 Dates in WP_Query / get_posts()

To avoid writing complex arrays when we need to perform a simple query, the following parameters are provided:

  • year (int) - 4 digits of the year (2013)
  • monthnum (int) - Month number (1 - 12)
  • w (int) - A week in a year (from 0 to 53)
  • day (int) - Day of the month (1 - 31)
  • hour (int) - Hour (0 - 23)
  • minute (int) - Minute (0 - 60)
  • second (int) - Second (0 - 60)
  • m (int) - YearMonth (201306)

For example, get the posts for 2015:

$posts = get_posts( "year=2015" )

Or get the posts for December 30, 2013:

$posts = get_posts( "year=2013&month=12&day=30" );

Or get this week's posts:

$posts = get_posts( array(
	'w'    => date('W'),
	'year' => date('Y')
) );
Extended use: parameter "date_query"

The WP_Query class since version 3.7. is extended by the WP_Date_Query class (parameter date_query) and allows you to get posts by date as you wish.

To retrieve posts by dates and still create complex queries, you need to use the parameter date_query, which works based on this class (WP_Date_Query).

Posts published from September 1-10, 2013:
$posts = get_posts(
	'date_query' => array(
		array( 'year' => 2013, 'month' => 9, 'day' => 10, 'compare' => '<=', ),
		array( 'year' => 2013, 'month' => 9, 'day' => 1, 'compare' => '>=', ),
	),
);

Or the same, but in a clearer form with before and after:

$posts = get_posts(
	'date_query' => array(
		'before' => array( 'year' => 2013, 'month' => 9, 'day' => 10 ),
		'after' => array( 'year' => 2013, 'month' => 9, 'day' => 1 ),
		'inclusive' => true, // inclusive
	),
);
Dates in strings

The parameters before and after can be specified as strings because they are handled by the PHP function strtotime(). Sometimes this is very convenient.

As in the first example, we get the posts from September 1-10, 2013:

$posts = get_posts(
	'date_query' => array(
		'before' => 'September 10th, 2013',
		'after' => 'September 1st, 2013',
		'inclusive' => true,
	),
);
Relative dates

In before and after you can specify relative dates.

Get the posts from the last 2 weeks:

$posts = get_posts( array(
	'date_query' => array(
		'after' => '2 weeks ago',
	),
) );

Or get all the posts for the last 2 months published on weekdays (Mon-Fri):

$posts = get_posts( array(
	'date_query' => array(
		'after' => '2 months ago',
		array(
			'dayofweek_iso' => array( 1, 5 ),
			'compare' => 'BETWEEN',
		),
	),
) );

Or get posts older than a year, but changed in the last month:

$query_args = array(
	'posts_per_page' => -1,
	'date_query' => array(
		array(
			'column' => 'post_date_gmt',
			'before' => '1 year ago',
		),
		array(
			'column' => 'post_modified_gmt',
			'after'  => '1 month ago',
		),
		'relation'  => 'AND',
	)
);

$posts = get_posts( $query_args );
0

#5 Dates in WP_Comment_Query / get_comments()

Just like for posts, we can use date queries to retrieve comments. For example, we can get all the comments published in the last week:

$comments = get_comments( array(
	'date_query' => array(
		array(
			'week' => gmdate( 'W' ) - 1
		)
	)
) );
0

#6 Dates in WP_User_Query / get_users()

Similarly, by retrieving posts and comments with date_query we can retrieve users by date of registration (field 'user_registered').

Get the users registered in the last month:

$users = get_users( array(
	'date_query' => array( 'after' => '1 month ago' )
) );

In this case 'date_query' query works only with field user_registered and this field is allowed in WP_Date_Query. And if, for example, we have additional field user_login (date when user was last logged in), then we cannot get all users logged in last month:

// will not work
$users = get_users(array(
	'date_query' => array( 'after' => '1 month ago', 'column' => 'user_login' )
));

To get around this limitation, we need to add the 'user_login' field to the allowed fields. To do this we use the filter 'date_query_valid_columns':

apply_filters( 'date_query_valid_columns', $valid_columns );

The code will look like this (not tested):

// add a new field
add_filter( 'date_query_valid_columns', function( $valid_columns ){
	$valid_columns[] = 'user_login';
	return $valid_columns;
} );

$users = get_users( array(
	'date_query' => array( 'after' => '1 month ago', 'column' => 'user_login' )
) );
0

#7 WP_Date_Query Generator:

https://GenerateWP.com/wp_date_query/

Changelog

Since 3.7.0 Introduced.

WP_Date_Query{} code WP 6.5.2

class WP_Date_Query {
	/**
	 * Array of date queries.
	 *
	 * See WP_Date_Query::__construct() for information on date query arguments.
	 *
	 * @since 3.7.0
	 * @var array
	 */
	public $queries = array();

	/**
	 * The default relation between top-level queries. Can be either 'AND' or 'OR'.
	 *
	 * @since 3.7.0
	 * @var string
	 */
	public $relation = 'AND';

	/**
	 * The column to query against. Can be changed via the query arguments.
	 *
	 * @since 3.7.0
	 * @var string
	 */
	public $column = 'post_date';

	/**
	 * The value comparison operator. Can be changed via the query arguments.
	 *
	 * @since 3.7.0
	 * @var string
	 */
	public $compare = '=';

	/**
	 * Supported time-related parameter keys.
	 *
	 * @since 4.1.0
	 * @var string[]
	 */
	public $time_keys = array( 'after', 'before', 'year', 'month', 'monthnum', 'week', 'w', 'dayofyear', 'day', 'dayofweek', 'dayofweek_iso', 'hour', 'minute', 'second' );

	/**
	 * Constructor.
	 *
	 * Time-related parameters that normally require integer values ('year', 'month', 'week', 'dayofyear', 'day',
	 * 'dayofweek', 'dayofweek_iso', 'hour', 'minute', 'second') accept arrays of integers for some values of
	 * 'compare'. When 'compare' is 'IN' or 'NOT IN', arrays are accepted; when 'compare' is 'BETWEEN' or 'NOT
	 * BETWEEN', arrays of two valid values are required. See individual argument descriptions for accepted values.
	 *
	 * @since 3.7.0
	 * @since 4.0.0 The $inclusive logic was updated to include all times within the date range.
	 * @since 4.1.0 Introduced 'dayofweek_iso' time type parameter.
	 *
	 * @param array  $date_query {
	 *     Array of date query clauses.
	 *
	 *     @type array ...$0 {
	 *         @type string $column   Optional. The column to query against. If undefined, inherits the value of
	 *                                the `$default_column` parameter. See WP_Date_Query::validate_column() and
	 *                                the {@see 'date_query_valid_columns'} filter for the list of accepted values.
	 *                                Default 'post_date'.
	 *         @type string $compare  Optional. The comparison operator. Accepts '=', '!=', '>', '>=', '<', '<=',
	 *                                'IN', 'NOT IN', 'BETWEEN', 'NOT BETWEEN'. Default '='.
	 *         @type string $relation Optional. The boolean relationship between the date queries. Accepts 'OR' or 'AND'.
	 *                                Default 'OR'.
	 *         @type array  ...$0 {
	 *             Optional. An array of first-order clause parameters, or another fully-formed date query.
	 *
	 *             @type string|array $before {
	 *                 Optional. Date to retrieve posts before. Accepts `strtotime()`-compatible string,
	 *                 or array of 'year', 'month', 'day' values.
	 *
	 *                 @type string $year  The four-digit year. Default empty. Accepts any four-digit year.
	 *                 @type string $month Optional when passing array.The month of the year.
	 *                                     Default (string:empty)|(array:1). Accepts numbers 1-12.
	 *                 @type string $day   Optional when passing array.The day of the month.
	 *                                     Default (string:empty)|(array:1). Accepts numbers 1-31.
	 *             }
	 *             @type string|array $after {
	 *                 Optional. Date to retrieve posts after. Accepts `strtotime()`-compatible string,
	 *                 or array of 'year', 'month', 'day' values.
	 *
	 *                 @type string $year  The four-digit year. Accepts any four-digit year. Default empty.
	 *                 @type string $month Optional when passing array. The month of the year. Accepts numbers 1-12.
	 *                                     Default (string:empty)|(array:12).
	 *                 @type string $day   Optional when passing array.The day of the month. Accepts numbers 1-31.
	 *                                     Default (string:empty)|(array:last day of month).
	 *             }
	 *             @type string       $column        Optional. Used to add a clause comparing a column other than
	 *                                               the column specified in the top-level `$column` parameter.
	 *                                               See WP_Date_Query::validate_column() and
	 *                                               the {@see 'date_query_valid_columns'} filter for the list
	 *                                               of accepted values. Default is the value of top-level `$column`.
	 *             @type string       $compare       Optional. The comparison operator. Accepts '=', '!=', '>', '>=',
	 *                                               '<', '<=', 'IN', 'NOT IN', 'BETWEEN', 'NOT BETWEEN'. 'IN',
	 *                                               'NOT IN', 'BETWEEN', and 'NOT BETWEEN'. Comparisons support
	 *                                               arrays in some time-related parameters. Default '='.
	 *             @type bool         $inclusive     Optional. Include results from dates specified in 'before' or
	 *                                               'after'. Default false.
	 *             @type int|int[]    $year          Optional. The four-digit year number. Accepts any four-digit year
	 *                                               or an array of years if `$compare` supports it. Default empty.
	 *             @type int|int[]    $month         Optional. The two-digit month number. Accepts numbers 1-12 or an
	 *                                               array of valid numbers if `$compare` supports it. Default empty.
	 *             @type int|int[]    $week          Optional. The week number of the year. Accepts numbers 0-53 or an
	 *                                               array of valid numbers if `$compare` supports it. Default empty.
	 *             @type int|int[]    $dayofyear     Optional. The day number of the year. Accepts numbers 1-366 or an
	 *                                               array of valid numbers if `$compare` supports it.
	 *             @type int|int[]    $day           Optional. The day of the month. Accepts numbers 1-31 or an array
	 *                                               of valid numbers if `$compare` supports it. Default empty.
	 *             @type int|int[]    $dayofweek     Optional. The day number of the week. Accepts numbers 1-7 (1 is
	 *                                               Sunday) or an array of valid numbers if `$compare` supports it.
	 *                                               Default empty.
	 *             @type int|int[]    $dayofweek_iso Optional. The day number of the week (ISO). Accepts numbers 1-7
	 *                                               (1 is Monday) or an array of valid numbers if `$compare` supports it.
	 *                                               Default empty.
	 *             @type int|int[]    $hour          Optional. The hour of the day. Accepts numbers 0-23 or an array
	 *                                               of valid numbers if `$compare` supports it. Default empty.
	 *             @type int|int[]    $minute        Optional. The minute of the hour. Accepts numbers 0-59 or an array
	 *                                               of valid numbers if `$compare` supports it. Default empty.
	 *             @type int|int[]    $second        Optional. The second of the minute. Accepts numbers 0-59 or an
	 *                                               array of valid numbers if `$compare` supports it. Default empty.
	 *         }
	 *     }
	 * }
	 * @param string $default_column Optional. Default column to query against. See WP_Date_Query::validate_column()
	 *                               and the {@see 'date_query_valid_columns'} filter for the list of accepted values.
	 *                               Default 'post_date'.
	 */
	public function __construct( $date_query, $default_column = 'post_date' ) {
		if ( empty( $date_query ) || ! is_array( $date_query ) ) {
			return;
		}

		if ( isset( $date_query['relation'] ) ) {
			$this->relation = $this->sanitize_relation( $date_query['relation'] );
		} else {
			$this->relation = 'AND';
		}

		// Support for passing time-based keys in the top level of the $date_query array.
		if ( ! isset( $date_query[0] ) ) {
			$date_query = array( $date_query );
		}

		if ( ! empty( $date_query['column'] ) ) {
			$date_query['column'] = esc_sql( $date_query['column'] );
		} else {
			$date_query['column'] = esc_sql( $default_column );
		}

		$this->column = $this->validate_column( $this->column );

		$this->compare = $this->get_compare( $date_query );

		$this->queries = $this->sanitize_query( $date_query );
	}

	/**
	 * Recursive-friendly query sanitizer.
	 *
	 * Ensures that each query-level clause has a 'relation' key, and that
	 * each first-order clause contains all the necessary keys from `$defaults`.
	 *
	 * @since 4.1.0
	 *
	 * @param array $queries
	 * @param array $parent_query
	 * @return array Sanitized queries.
	 */
	public function sanitize_query( $queries, $parent_query = null ) {
		$cleaned_query = array();

		$defaults = array(
			'column'   => 'post_date',
			'compare'  => '=',
			'relation' => 'AND',
		);

		// Numeric keys should always have array values.
		foreach ( $queries as $qkey => $qvalue ) {
			if ( is_numeric( $qkey ) && ! is_array( $qvalue ) ) {
				unset( $queries[ $qkey ] );
			}
		}

		// Each query should have a value for each default key. Inherit from the parent when possible.
		foreach ( $defaults as $dkey => $dvalue ) {
			if ( isset( $queries[ $dkey ] ) ) {
				continue;
			}

			if ( isset( $parent_query[ $dkey ] ) ) {
				$queries[ $dkey ] = $parent_query[ $dkey ];
			} else {
				$queries[ $dkey ] = $dvalue;
			}
		}

		// Validate the dates passed in the query.
		if ( $this->is_first_order_clause( $queries ) ) {
			$this->validate_date_values( $queries );
		}

		// Sanitize the relation parameter.
		$queries['relation'] = $this->sanitize_relation( $queries['relation'] );

		foreach ( $queries as $key => $q ) {
			if ( ! is_array( $q ) || in_array( $key, $this->time_keys, true ) ) {
				// This is a first-order query. Trust the values and sanitize when building SQL.
				$cleaned_query[ $key ] = $q;
			} else {
				// Any array without a time key is another query, so we recurse.
				$cleaned_query[] = $this->sanitize_query( $q, $queries );
			}
		}

		return $cleaned_query;
	}

	/**
	 * Determines whether this is a first-order clause.
	 *
	 * Checks to see if the current clause has any time-related keys.
	 * If so, it's first-order.
	 *
	 * @since 4.1.0
	 *
	 * @param array $query Query clause.
	 * @return bool True if this is a first-order clause.
	 */
	protected function is_first_order_clause( $query ) {
		$time_keys = array_intersect( $this->time_keys, array_keys( $query ) );
		return ! empty( $time_keys );
	}

	/**
	 * Determines and validates what comparison operator to use.
	 *
	 * @since 3.7.0
	 *
	 * @param array $query A date query or a date subquery.
	 * @return string The comparison operator.
	 */
	public function get_compare( $query ) {
		if ( ! empty( $query['compare'] )
			&& in_array( $query['compare'], array( '=', '!=', '>', '>=', '<', '<=', 'IN', 'NOT IN', 'BETWEEN', 'NOT BETWEEN' ), true )
		) {
			return strtoupper( $query['compare'] );
		}

		return $this->compare;
	}

	/**
	 * Validates the given date_query values and triggers errors if something is not valid.
	 *
	 * Note that date queries with invalid date ranges are allowed to
	 * continue (though of course no items will be found for impossible dates).
	 * This method only generates debug notices for these cases.
	 *
	 * @since 4.1.0
	 *
	 * @param array $date_query The date_query array.
	 * @return bool True if all values in the query are valid, false if one or more fail.
	 */
	public function validate_date_values( $date_query = array() ) {
		if ( empty( $date_query ) ) {
			return false;
		}

		$valid = true;

		/*
		 * Validate 'before' and 'after' up front, then let the
		 * validation routine continue to be sure that all invalid
		 * values generate errors too.
		 */
		if ( array_key_exists( 'before', $date_query ) && is_array( $date_query['before'] ) ) {
			$valid = $this->validate_date_values( $date_query['before'] );
		}

		if ( array_key_exists( 'after', $date_query ) && is_array( $date_query['after'] ) ) {
			$valid = $this->validate_date_values( $date_query['after'] );
		}

		// Array containing all min-max checks.
		$min_max_checks = array();

		// Days per year.
		if ( array_key_exists( 'year', $date_query ) ) {
			/*
			 * If a year exists in the date query, we can use it to get the days.
			 * If multiple years are provided (as in a BETWEEN), use the first one.
			 */
			if ( is_array( $date_query['year'] ) ) {
				$_year = reset( $date_query['year'] );
			} else {
				$_year = $date_query['year'];
			}

			$max_days_of_year = gmdate( 'z', mktime( 0, 0, 0, 12, 31, $_year ) ) + 1;
		} else {
			// Otherwise we use the max of 366 (leap-year).
			$max_days_of_year = 366;
		}

		$min_max_checks['dayofyear'] = array(
			'min' => 1,
			'max' => $max_days_of_year,
		);

		// Days per week.
		$min_max_checks['dayofweek'] = array(
			'min' => 1,
			'max' => 7,
		);

		// Days per week.
		$min_max_checks['dayofweek_iso'] = array(
			'min' => 1,
			'max' => 7,
		);

		// Months per year.
		$min_max_checks['month'] = array(
			'min' => 1,
			'max' => 12,
		);

		// Weeks per year.
		if ( isset( $_year ) ) {
			/*
			 * If we have a specific year, use it to calculate number of weeks.
			 * Note: the number of weeks in a year is the date in which Dec 28 appears.
			 */
			$week_count = gmdate( 'W', mktime( 0, 0, 0, 12, 28, $_year ) );

		} else {
			// Otherwise set the week-count to a maximum of 53.
			$week_count = 53;
		}

		$min_max_checks['week'] = array(
			'min' => 1,
			'max' => $week_count,
		);

		// Days per month.
		$min_max_checks['day'] = array(
			'min' => 1,
			'max' => 31,
		);

		// Hours per day.
		$min_max_checks['hour'] = array(
			'min' => 0,
			'max' => 23,
		);

		// Minutes per hour.
		$min_max_checks['minute'] = array(
			'min' => 0,
			'max' => 59,
		);

		// Seconds per minute.
		$min_max_checks['second'] = array(
			'min' => 0,
			'max' => 59,
		);

		// Concatenate and throw a notice for each invalid value.
		foreach ( $min_max_checks as $key => $check ) {
			if ( ! array_key_exists( $key, $date_query ) ) {
				continue;
			}

			// Throw a notice for each failing value.
			foreach ( (array) $date_query[ $key ] as $_value ) {
				$is_between = $_value >= $check['min'] && $_value <= $check['max'];

				if ( ! is_numeric( $_value ) || ! $is_between ) {
					$error = sprintf(
						/* translators: Date query invalid date message. 1: Invalid value, 2: Type of value, 3: Minimum valid value, 4: Maximum valid value. */
						__( 'Invalid value %1$s for %2$s. Expected value should be between %3$s and %4$s.' ),
						'<code>' . esc_html( $_value ) . '</code>',
						'<code>' . esc_html( $key ) . '</code>',
						'<code>' . esc_html( $check['min'] ) . '</code>',
						'<code>' . esc_html( $check['max'] ) . '</code>'
					);

					_doing_it_wrong( __CLASS__, $error, '4.1.0' );

					$valid = false;
				}
			}
		}

		// If we already have invalid date messages, don't bother running through checkdate().
		if ( ! $valid ) {
			return $valid;
		}

		$day_month_year_error_msg = '';

		$day_exists   = array_key_exists( 'day', $date_query ) && is_numeric( $date_query['day'] );
		$month_exists = array_key_exists( 'month', $date_query ) && is_numeric( $date_query['month'] );
		$year_exists  = array_key_exists( 'year', $date_query ) && is_numeric( $date_query['year'] );

		if ( $day_exists && $month_exists && $year_exists ) {
			// 1. Checking day, month, year combination.
			if ( ! wp_checkdate( $date_query['month'], $date_query['day'], $date_query['year'], sprintf( '%s-%s-%s', $date_query['year'], $date_query['month'], $date_query['day'] ) ) ) {
				$day_month_year_error_msg = sprintf(
					/* translators: 1: Year, 2: Month, 3: Day of month. */
					__( 'The following values do not describe a valid date: year %1$s, month %2$s, day %3$s.' ),
					'<code>' . esc_html( $date_query['year'] ) . '</code>',
					'<code>' . esc_html( $date_query['month'] ) . '</code>',
					'<code>' . esc_html( $date_query['day'] ) . '</code>'
				);

				$valid = false;
			}
		} elseif ( $day_exists && $month_exists ) {
			/*
			 * 2. checking day, month combination
			 * We use 2012 because, as a leap year, it's the most permissive.
			 */
			if ( ! wp_checkdate( $date_query['month'], $date_query['day'], 2012, sprintf( '2012-%s-%s', $date_query['month'], $date_query['day'] ) ) ) {
				$day_month_year_error_msg = sprintf(
					/* translators: 1: Month, 2: Day of month. */
					__( 'The following values do not describe a valid date: month %1$s, day %2$s.' ),
					'<code>' . esc_html( $date_query['month'] ) . '</code>',
					'<code>' . esc_html( $date_query['day'] ) . '</code>'
				);

				$valid = false;
			}
		}

		if ( ! empty( $day_month_year_error_msg ) ) {
			_doing_it_wrong( __CLASS__, $day_month_year_error_msg, '4.1.0' );
		}

		return $valid;
	}

	/**
	 * Validates a column name parameter.
	 *
	 * Column names without a table prefix (like 'post_date') are checked against a list of
	 * allowed and known tables, and then, if found, have a table prefix (such as 'wp_posts.')
	 * prepended. Prefixed column names (such as 'wp_posts.post_date') bypass this allowed
	 * check, and are only sanitized to remove illegal characters.
	 *
	 * @since 3.7.0
	 *
	 * @global wpdb $wpdb WordPress database abstraction object.
	 *
	 * @param string $column The user-supplied column name.
	 * @return string A validated column name value.
	 */
	public function validate_column( $column ) {
		global $wpdb;

		$valid_columns = array(
			'post_date',
			'post_date_gmt',
			'post_modified',
			'post_modified_gmt',
			'comment_date',
			'comment_date_gmt',
			'user_registered',
			'registered',
			'last_updated',
		);

		// Attempt to detect a table prefix.
		if ( ! str_contains( $column, '.' ) ) {
			/**
			 * Filters the list of valid date query columns.
			 *
			 * @since 3.7.0
			 * @since 4.1.0 Added 'user_registered' to the default recognized columns.
			 * @since 4.6.0 Added 'registered' and 'last_updated' to the default recognized columns.
			 *
			 * @param string[] $valid_columns An array of valid date query columns. Defaults
			 *                                are 'post_date', 'post_date_gmt', 'post_modified',
			 *                                'post_modified_gmt', 'comment_date', 'comment_date_gmt',
			 *                                'user_registered', 'registered', 'last_updated'.
			 */
			if ( ! in_array( $column, apply_filters( 'date_query_valid_columns', $valid_columns ), true ) ) {
				$column = 'post_date';
			}

			$known_columns = array(
				$wpdb->posts    => array(
					'post_date',
					'post_date_gmt',
					'post_modified',
					'post_modified_gmt',
				),
				$wpdb->comments => array(
					'comment_date',
					'comment_date_gmt',
				),
				$wpdb->users    => array(
					'user_registered',
				),
				$wpdb->blogs    => array(
					'registered',
					'last_updated',
				),
			);

			// If it's a known column name, add the appropriate table prefix.
			foreach ( $known_columns as $table_name => $table_columns ) {
				if ( in_array( $column, $table_columns, true ) ) {
					$column = $table_name . '.' . $column;
					break;
				}
			}
		}

		// Remove unsafe characters.
		return preg_replace( '/[^a-zA-Z0-9_$\.]/', '', $column );
	}

	/**
	 * Generates WHERE clause to be appended to a main query.
	 *
	 * @since 3.7.0
	 *
	 * @return string MySQL WHERE clause.
	 */
	public function get_sql() {
		$sql = $this->get_sql_clauses();

		$where = $sql['where'];

		/**
		 * Filters the date query WHERE clause.
		 *
		 * @since 3.7.0
		 *
		 * @param string        $where WHERE clause of the date query.
		 * @param WP_Date_Query $query The WP_Date_Query instance.
		 */
		return apply_filters( 'get_date_sql', $where, $this );
	}

	/**
	 * Generates SQL clauses to be appended to a main query.
	 *
	 * Called by the public WP_Date_Query::get_sql(), this method is abstracted
	 * out to maintain parity with the other Query classes.
	 *
	 * @since 4.1.0
	 *
	 * @return string[] {
	 *     Array containing JOIN and WHERE SQL clauses to append to the main query.
	 *
	 *     @type string $join  SQL fragment to append to the main JOIN clause.
	 *     @type string $where SQL fragment to append to the main WHERE clause.
	 * }
	 */
	protected function get_sql_clauses() {
		$sql = $this->get_sql_for_query( $this->queries );

		if ( ! empty( $sql['where'] ) ) {
			$sql['where'] = ' AND ' . $sql['where'];
		}

		return $sql;
	}

	/**
	 * Generates SQL clauses for a single query array.
	 *
	 * If nested subqueries are found, this method recurses the tree to
	 * produce the properly nested SQL.
	 *
	 * @since 4.1.0
	 *
	 * @param array $query Query to parse.
	 * @param int   $depth Optional. Number of tree levels deep we currently are.
	 *                     Used to calculate indentation. Default 0.
	 * @return array {
	 *     Array containing JOIN and WHERE SQL clauses to append to a single query array.
	 *
	 *     @type string $join  SQL fragment to append to the main JOIN clause.
	 *     @type string $where SQL fragment to append to the main WHERE clause.
	 * }
	 */
	protected function get_sql_for_query( $query, $depth = 0 ) {
		$sql_chunks = array(
			'join'  => array(),
			'where' => array(),
		);

		$sql = array(
			'join'  => '',
			'where' => '',
		);

		$indent = '';
		for ( $i = 0; $i < $depth; $i++ ) {
			$indent .= '  ';
		}

		foreach ( $query as $key => $clause ) {
			if ( 'relation' === $key ) {
				$relation = $query['relation'];
			} elseif ( is_array( $clause ) ) {

				// This is a first-order clause.
				if ( $this->is_first_order_clause( $clause ) ) {
					$clause_sql = $this->get_sql_for_clause( $clause, $query );

					$where_count = count( $clause_sql['where'] );
					if ( ! $where_count ) {
						$sql_chunks['where'][] = '';
					} elseif ( 1 === $where_count ) {
						$sql_chunks['where'][] = $clause_sql['where'][0];
					} else {
						$sql_chunks['where'][] = '( ' . implode( ' AND ', $clause_sql['where'] ) . ' )';
					}

					$sql_chunks['join'] = array_merge( $sql_chunks['join'], $clause_sql['join'] );
					// This is a subquery, so we recurse.
				} else {
					$clause_sql = $this->get_sql_for_query( $clause, $depth + 1 );

					$sql_chunks['where'][] = $clause_sql['where'];
					$sql_chunks['join'][]  = $clause_sql['join'];
				}
			}
		}

		// Filter to remove empties.
		$sql_chunks['join']  = array_filter( $sql_chunks['join'] );
		$sql_chunks['where'] = array_filter( $sql_chunks['where'] );

		if ( empty( $relation ) ) {
			$relation = 'AND';
		}

		// Filter duplicate JOIN clauses and combine into a single string.
		if ( ! empty( $sql_chunks['join'] ) ) {
			$sql['join'] = implode( ' ', array_unique( $sql_chunks['join'] ) );
		}

		// Generate a single WHERE clause with proper brackets and indentation.
		if ( ! empty( $sql_chunks['where'] ) ) {
			$sql['where'] = '( ' . "\n  " . $indent . implode( ' ' . "\n  " . $indent . $relation . ' ' . "\n  " . $indent, $sql_chunks['where'] ) . "\n" . $indent . ')';
		}

		return $sql;
	}

	/**
	 * Turns a single date clause into pieces for a WHERE clause.
	 *
	 * A wrapper for get_sql_for_clause(), included here for backward
	 * compatibility while retaining the naming convention across Query classes.
	 *
	 * @since 3.7.0
	 *
	 * @param array $query Date query arguments.
	 * @return array {
	 *     Array containing JOIN and WHERE SQL clauses to append to the main query.
	 *
	 *     @type string[] $join  Array of SQL fragments to append to the main JOIN clause.
	 *     @type string[] $where Array of SQL fragments to append to the main WHERE clause.
	 * }
	 */
	protected function get_sql_for_subquery( $query ) {
		return $this->get_sql_for_clause( $query, '' );
	}

	/**
	 * Turns a first-order date query into SQL for a WHERE clause.
	 *
	 * @since 4.1.0
	 *
	 * @global wpdb $wpdb WordPress database abstraction object.
	 *
	 * @param array $query        Date query clause.
	 * @param array $parent_query Parent query of the current date query.
	 * @return array {
	 *     Array containing JOIN and WHERE SQL clauses to append to the main query.
	 *
	 *     @type string[] $join  Array of SQL fragments to append to the main JOIN clause.
	 *     @type string[] $where Array of SQL fragments to append to the main WHERE clause.
	 * }
	 */
	protected function get_sql_for_clause( $query, $parent_query ) {
		global $wpdb;

		// The sub-parts of a $where part.
		$where_parts = array();

		$column = ( ! empty( $query['column'] ) ) ? esc_sql( $query['column'] ) : $this->column;

		$column = $this->validate_column( $column );

		$compare = $this->get_compare( $query );

		$inclusive = ! empty( $query['inclusive'] );

		// Assign greater- and less-than values.
		$lt = '<';
		$gt = '>';

		if ( $inclusive ) {
			$lt .= '=';
			$gt .= '=';
		}

		// Range queries.
		if ( ! empty( $query['after'] ) ) {
			$where_parts[] = $wpdb->prepare( "$column $gt %s", $this->build_mysql_datetime( $query['after'], ! $inclusive ) );
		}
		if ( ! empty( $query['before'] ) ) {
			$where_parts[] = $wpdb->prepare( "$column $lt %s", $this->build_mysql_datetime( $query['before'], $inclusive ) );
		}
		// Specific value queries.

		$date_units = array(
			'YEAR'           => array( 'year' ),
			'MONTH'          => array( 'month', 'monthnum' ),
			'_wp_mysql_week' => array( 'week', 'w' ),
			'DAYOFYEAR'      => array( 'dayofyear' ),
			'DAYOFMONTH'     => array( 'day' ),
			'DAYOFWEEK'      => array( 'dayofweek' ),
			'WEEKDAY'        => array( 'dayofweek_iso' ),
		);

		// Check of the possible date units and add them to the query.
		foreach ( $date_units as $sql_part => $query_parts ) {
			foreach ( $query_parts as $query_part ) {
				if ( isset( $query[ $query_part ] ) ) {
					$value = $this->build_value( $compare, $query[ $query_part ] );
					if ( $value ) {
						switch ( $sql_part ) {
							case '_wp_mysql_week':
								$where_parts[] = _wp_mysql_week( $column ) . " $compare $value";
								break;
							case 'WEEKDAY':
								$where_parts[] = "$sql_part( $column ) + 1 $compare $value";
								break;
							default:
								$where_parts[] = "$sql_part( $column ) $compare $value";
						}

						break;
					}
				}
			}
		}

		if ( isset( $query['hour'] ) || isset( $query['minute'] ) || isset( $query['second'] ) ) {
			// Avoid notices.
			foreach ( array( 'hour', 'minute', 'second' ) as $unit ) {
				if ( ! isset( $query[ $unit ] ) ) {
					$query[ $unit ] = null;
				}
			}

			$time_query = $this->build_time_query( $column, $compare, $query['hour'], $query['minute'], $query['second'] );
			if ( $time_query ) {
				$where_parts[] = $time_query;
			}
		}

		/*
		 * Return an array of 'join' and 'where' for compatibility
		 * with other query classes.
		 */
		return array(
			'where' => $where_parts,
			'join'  => array(),
		);
	}

	/**
	 * Builds and validates a value string based on the comparison operator.
	 *
	 * @since 3.7.0
	 *
	 * @param string       $compare The compare operator to use.
	 * @param string|array $value   The value.
	 * @return string|false|int The value to be used in SQL or false on error.
	 */
	public function build_value( $compare, $value ) {
		if ( ! isset( $value ) ) {
			return false;
		}

		switch ( $compare ) {
			case 'IN':
			case 'NOT IN':
				$value = (array) $value;

				// Remove non-numeric values.
				$value = array_filter( $value, 'is_numeric' );

				if ( empty( $value ) ) {
					return false;
				}

				return '(' . implode( ',', array_map( 'intval', $value ) ) . ')';

			case 'BETWEEN':
			case 'NOT BETWEEN':
				if ( ! is_array( $value ) || 2 !== count( $value ) ) {
					$value = array( $value, $value );
				} else {
					$value = array_values( $value );
				}

				// If either value is non-numeric, bail.
				foreach ( $value as $v ) {
					if ( ! is_numeric( $v ) ) {
						return false;
					}
				}

				$value = array_map( 'intval', $value );

				return $value[0] . ' AND ' . $value[1];

			default:
				if ( ! is_numeric( $value ) ) {
					return false;
				}

				return (int) $value;
		}
	}

	/**
	 * Builds a MySQL format date/time based on some query parameters.
	 *
	 * You can pass an array of values (year, month, etc.) with missing parameter values being defaulted to
	 * either the maximum or minimum values (controlled by the $default_to parameter). Alternatively you can
	 * pass a string that will be passed to date_create().
	 *
	 * @since 3.7.0
	 *
	 * @param string|array $datetime       An array of parameters or a strtotime() string.
	 * @param bool         $default_to_max Whether to round up incomplete dates. Supported by values
	 *                                     of $datetime that are arrays, or string values that are a
	 *                                     subset of MySQL date format ('Y', 'Y-m', 'Y-m-d', 'Y-m-d H:i').
	 *                                     Default: false.
	 * @return string|false A MySQL format date/time or false on failure.
	 */
	public function build_mysql_datetime( $datetime, $default_to_max = false ) {
		if ( ! is_array( $datetime ) ) {

			/*
			 * Try to parse some common date formats, so we can detect
			 * the level of precision and support the 'inclusive' parameter.
			 */
			if ( preg_match( '/^(\d{4})$/', $datetime, $matches ) ) {
				// Y
				$datetime = array(
					'year' => (int) $matches[1],
				);

			} elseif ( preg_match( '/^(\d{4})\-(\d{2})$/', $datetime, $matches ) ) {
				// Y-m
				$datetime = array(
					'year'  => (int) $matches[1],
					'month' => (int) $matches[2],
				);

			} elseif ( preg_match( '/^(\d{4})\-(\d{2})\-(\d{2})$/', $datetime, $matches ) ) {
				// Y-m-d
				$datetime = array(
					'year'  => (int) $matches[1],
					'month' => (int) $matches[2],
					'day'   => (int) $matches[3],
				);

			} elseif ( preg_match( '/^(\d{4})\-(\d{2})\-(\d{2}) (\d{2}):(\d{2})$/', $datetime, $matches ) ) {
				// Y-m-d H:i
				$datetime = array(
					'year'   => (int) $matches[1],
					'month'  => (int) $matches[2],
					'day'    => (int) $matches[3],
					'hour'   => (int) $matches[4],
					'minute' => (int) $matches[5],
				);
			}

			// If no match is found, we don't support default_to_max.
			if ( ! is_array( $datetime ) ) {
				$wp_timezone = wp_timezone();

				// Assume local timezone if not provided.
				$dt = date_create( $datetime, $wp_timezone );

				if ( false === $dt ) {
					return gmdate( 'Y-m-d H:i:s', false );
				}

				return $dt->setTimezone( $wp_timezone )->format( 'Y-m-d H:i:s' );
			}
		}

		$datetime = array_map( 'absint', $datetime );

		if ( ! isset( $datetime['year'] ) ) {
			$datetime['year'] = current_time( 'Y' );
		}

		if ( ! isset( $datetime['month'] ) ) {
			$datetime['month'] = ( $default_to_max ) ? 12 : 1;
		}

		if ( ! isset( $datetime['day'] ) ) {
			$datetime['day'] = ( $default_to_max ) ? (int) gmdate( 't', mktime( 0, 0, 0, $datetime['month'], 1, $datetime['year'] ) ) : 1;
		}

		if ( ! isset( $datetime['hour'] ) ) {
			$datetime['hour'] = ( $default_to_max ) ? 23 : 0;
		}

		if ( ! isset( $datetime['minute'] ) ) {
			$datetime['minute'] = ( $default_to_max ) ? 59 : 0;
		}

		if ( ! isset( $datetime['second'] ) ) {
			$datetime['second'] = ( $default_to_max ) ? 59 : 0;
		}

		return sprintf( '%04d-%02d-%02d %02d:%02d:%02d', $datetime['year'], $datetime['month'], $datetime['day'], $datetime['hour'], $datetime['minute'], $datetime['second'] );
	}

	/**
	 * Builds a query string for comparing time values (hour, minute, second).
	 *
	 * If just hour, minute, or second is set than a normal comparison will be done.
	 * However if multiple values are passed, a pseudo-decimal time will be created
	 * in order to be able to accurately compare against.
	 *
	 * @since 3.7.0
	 *
	 * @global wpdb $wpdb WordPress database abstraction object.
	 *
	 * @param string   $column  The column to query against. Needs to be pre-validated!
	 * @param string   $compare The comparison operator. Needs to be pre-validated!
	 * @param int|null $hour    Optional. An hour value (0-23).
	 * @param int|null $minute  Optional. A minute value (0-59).
	 * @param int|null $second  Optional. A second value (0-59).
	 * @return string|false A query part or false on failure.
	 */
	public function build_time_query( $column, $compare, $hour = null, $minute = null, $second = null ) {
		global $wpdb;

		// Have to have at least one.
		if ( ! isset( $hour ) && ! isset( $minute ) && ! isset( $second ) ) {
			return false;
		}

		// Complex combined queries aren't supported for multi-value queries.
		if ( in_array( $compare, array( 'IN', 'NOT IN', 'BETWEEN', 'NOT BETWEEN' ), true ) ) {
			$return = array();

			$value = $this->build_value( $compare, $hour );
			if ( false !== $value ) {
				$return[] = "HOUR( $column ) $compare $value";
			}

			$value = $this->build_value( $compare, $minute );
			if ( false !== $value ) {
				$return[] = "MINUTE( $column ) $compare $value";
			}

			$value = $this->build_value( $compare, $second );
			if ( false !== $value ) {
				$return[] = "SECOND( $column ) $compare $value";
			}

			return implode( ' AND ', $return );
		}

		// Cases where just one unit is set.
		if ( isset( $hour ) && ! isset( $minute ) && ! isset( $second ) ) {
			$value = $this->build_value( $compare, $hour );
			if ( false !== $value ) {
				return "HOUR( $column ) $compare $value";
			}
		} elseif ( ! isset( $hour ) && isset( $minute ) && ! isset( $second ) ) {
			$value = $this->build_value( $compare, $minute );
			if ( false !== $value ) {
				return "MINUTE( $column ) $compare $value";
			}
		} elseif ( ! isset( $hour ) && ! isset( $minute ) && isset( $second ) ) {
			$value = $this->build_value( $compare, $second );
			if ( false !== $value ) {
				return "SECOND( $column ) $compare $value";
			}
		}

		// Single units were already handled. Since hour & second isn't allowed, minute must to be set.
		if ( ! isset( $minute ) ) {
			return false;
		}

		$format = '';
		$time   = '';

		// Hour.
		if ( null !== $hour ) {
			$format .= '%H.';
			$time   .= sprintf( '%02d', $hour ) . '.';
		} else {
			$format .= '0.';
			$time   .= '0.';
		}

		// Minute.
		$format .= '%i';
		$time   .= sprintf( '%02d', $minute );

		if ( isset( $second ) ) {
			$format .= '%s';
			$time   .= sprintf( '%02d', $second );
		}

		return $wpdb->prepare( "DATE_FORMAT( $column, %s ) $compare %f", $format, $time );
	}

	/**
	 * Sanitizes a 'relation' operator.
	 *
	 * @since 6.0.3
	 *
	 * @param string $relation Raw relation key from the query argument.
	 * @return string Sanitized relation. Either 'AND' or 'OR'.
	 */
	public function sanitize_relation( $relation ) {
		if ( 'OR' === strtoupper( $relation ) ) {
			return 'OR';
		} else {
			return 'AND';
		}
	}
}