wpdb::get_results() │ public │ WP 0.71

Retrieves an entire SQL result set from the database (i.e., many rows).

Executes a SQL query and returns the entire SQL result.

Method of the class: wpdb{}

No Hooks.

Return

Array|Object|null. Database query results.

Usage

global $wpdb;
$wpdb->get_results( $query, $output );
$query(string)
SQL query.
Default: null
$output(string)
Any of ARRAY_A | ARRAY_N | OBJECT | OBJECT_K constants. With one of the first three, return an array of rows indexed from 0 by SQL result row number. Each row is an associative array (column => value, ...), a numerically indexed array (0 => value, ...), or an object ( ->column = value ), respectively. With OBJECT_K, return an associative array of row objects keyed by the value of each row's first column's value. Duplicate keys are discarded.
Default: OBJECT

Examples

0

#1 Get the IDs and titles of drafts whose author ID = 5 and display the posts titles 

$fivesdrafts = $wpdb->get_results( 
	"SELECT ID, post_title FROM $wpdb->posts WHERE post_status = 'draft' AND post_author = 5"
);

foreach ( $fivesdrafts as $fivesdraft ) {
	echo $fivesdraft->post_title;
}
0

#2 Example of a complex query with GROUP BY (reviews in WooCommerce) 

/**
* Returns the results of the rating (reviews in WooCommerce) grouped by ratings
*
* @param int $post_id post ID
*
* @return array of objects, where each object is a lumped data on one of the grades
*/
function get_cnt_rating_reviews_one_product( $post_id ){
	global $wpdb;

	return $wpdb->get_results( $wpdb->prepare(
		"
		SELECT COUNT(meta.meta_id) as num, meta.meta_value
		FROM $wpdb->comments as comments
		INNER JOIN $wpdb->commentmeta as meta ON comments.comment_ID = meta.comment_id
		WHERE comments.comment_post_ID = %d AND meta_key = 'rating'
		GROUP BY meta.meta_value;
		",
		$post_id
	) );

}

// usage
get_cnt_rating_reviews_one_product( 4350 );
0

#3 Display the links to the author's drafts with ID = 5 

<?php
$fivesdrafts = $wpdb->get_results( 
	"SELECT * FROM $wpdb->posts WHERE post_status = 'draft' AND post_author = 5"
);

if( $fivesdrafts ) :
	foreach( $fivesdrafts as $post ){
		setup_postdata($post);
		?>
			<h2><a href="<?php the_permalink(); ?>" rel="bookmark"
				title="Permanent Link to <?php the_title(); ?>"><?php the_title(); ?></a></h2>
		<?php
	}
	else :
	?>
	<h2> Not found</h2>
	<?php 
endif;
?>
0

#4 Error handling

This is how to intercept errors from get_results():

global $wpdb;
$result = $wpdb->get_results( "SELECT * FROM invalid query" );

if ( $wpdb->last_error ) {
  echo 'wpdb error: ' . $wpdb->last_error;
}

Changelog

Since 0.71 Introduced.

wpdb::get_results() code WP 6.5.2

wp-includes/class-wpdb.php 
public function get_results( $query = null, $output = OBJECT ) {
	$this->func_call = "\$db->get_results(\"$query\", $output)";

	if ( $query ) {
		if ( $this->check_current_query && $this->check_safe_collation( $query ) ) {
			$this->check_current_query = false;
		}

		$this->query( $query );
	} else {
		return null;
	}

	$new_array = array();
	if ( OBJECT === $output ) {
		// Return an integer-keyed array of row objects.
		return $this->last_result;
	} elseif ( OBJECT_K === $output ) {
		/*
		 * Return an array of row objects with keys from column 1.
		 * (Duplicates are discarded.)
		 */
		if ( $this->last_result ) {
			foreach ( $this->last_result as $row ) {
				$var_by_ref = get_object_vars( $row );
				$key        = array_shift( $var_by_ref );
				if ( ! isset( $new_array[ $key ] ) ) {
					$new_array[ $key ] = $row;
				}
			}
		}
		return $new_array;
	} elseif ( ARRAY_A === $output || ARRAY_N === $output ) {
		// Return an integer-keyed array of...
		if ( $this->last_result ) {
			if ( ARRAY_N === $output ) {
				foreach ( (array) $this->last_result as $row ) {
					// ...integer-keyed row arrays.
					$new_array[] = array_values( get_object_vars( $row ) );
				}
			} else {
				foreach ( (array) $this->last_result as $row ) {
					// ...column name-keyed row arrays.
					$new_array[] = get_object_vars( $row );
				}
			}
		}
		return $new_array;
	} elseif ( strtoupper( $output ) === OBJECT ) {
		// Back compat for OBJECT being previously case-insensitive.
		return $this->last_result;
	}
	return null;
}

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