WordPress at a glance
filter is not described

get_meta_sql filter-hook . WP 3.1.0

Filters the meta query's generated SQL.

Usage

add_filter( 'get_meta_sql', 'filter_function_name_657', 10, 6 );
function filter_function_name_657( $clauses, $queries, $type, $primary_table, $primary_id_column, $context ){
	// filter...

	return $clauses;
}
$clauses(array)
Array containing the query's JOIN and WHERE clauses.
$queries(array)
Array of meta queries.
$type(string)
Type of meta.
$primary_table(string)
Primary table.
$primary_id_column(string)
Primary column ID.
$context(object)
The main query object.

Where the hook is called

WP_Meta_Query::get_sql()
wp-includes/class-wp-meta-query.php 343
return apply_filters_ref_array( 'get_meta_sql', array( $sql, $this->queries, $type, $primary_table, $primary_id_column, $context ) );

Where the hook is used (in WP core)

Does not used.