WordPress at a glance
function is not described

wpdb::get_var() public WP 0.71

Retrieves one variable from the database.

Executes a SQL query and returns the value from the SQL result. If the SQL result contains more than one column and/or more than one row, the value in the column and row specified is returned. If $query is null, the value in the specified column and row from the previous SQL result is returned.

It's a method of the class: wpdb{}

No Hooks.

Return

String/null. Database query result (as string), or null on failure.

Usage

$wpdb = new wpdb();
$wpdb->get_var( $query, $x, $y );
$query(string/null)
SQL query.
Default: null, use the result from the previous query
$x(int)
Column of value to return. Indexed from 0.
Default: 0
$y(int)
Row of value to return. Indexed from 0.
Default: 0

Changelog

Since 0.71 Introduced.

Code of wpdb::get_var() WP 5.5.1

<?php
public function get_var( $query = null, $x = 0, $y = 0 ) {
	$this->func_call = "\$db->get_var(\"$query\", $x, $y)";

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

	if ( $query ) {
		$this->query( $query );
	}

	// Extract var out of cached results based on x,y vals.
	if ( ! empty( $this->last_result[ $y ] ) ) {
		$values = array_values( get_object_vars( $this->last_result[ $y ] ) );
	}

	// If there is a value return it, else return null.
	return ( isset( $values[ $x ] ) && '' !== $values[ $x ] ) ? $values[ $x ] : null;
}