wp-includes/class-wpdb.php:3023Retrieves one value from the database.
$querystring|nulloptionalnull$xintoptional0$yintoptional0string|null public function get_var( $query = null, $x = 0, $y = 0 ) { $this->func_call = "\$db->get_var(\"$query\", $x, $y)"; if ( $query ) { if ( $this->check_current_query && $this->check_safe_collation( $query ) ) { $this->check_current_query = false; } $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; }Introduced in 0.71. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/class-wpdb.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.