/**
* Generates SQL clauses to be added to the query.
*
* @access public
* @since 8.2.5
*
* @param string $type Type of meta, eg 'entry', 'term'.
* @param string $primary_table Database table where the object being filtered is stored (eg CN_ENTRY_TABLE).
* @param string $primary_id_column ID column for the filtered object in $primary_table.
* @param mixed $context object|null Optional. The main query object.
*
* @return array {
* 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 $where SQL fragment to append to the main WHERE clause.
* }
*/
public function get_sql($type, $primary_table, $primary_id_column, $context = null)
{
$this->meta_table = cnMeta::tableName($type);
$this->meta_id_column = sanitize_key($type . '_id');
$this->primary_table = $primary_table;
$this->primary_id_column = $primary_id_column;
$sql = $this->get_sql_clauses();
/*
* If any JOINs are LEFT JOINs (as in the case of NOT EXISTS), then all JOINs should
* be LEFT. Otherwise posts with no metadata will be excluded from results.
*/
if (false !== strpos($sql['join'], 'LEFT JOIN')) {
$sql['join'] = str_replace('INNER JOIN', 'LEFT JOIN', $sql['join']);
}
/**
* Filter the meta query's generated SQL.
*
* @since 8.2.5
*
* @param array $args {
* An array of meta query SQL arguments.
*
* @type array $clauses Array containing the query's JOIN and WHERE clauses.
* @type array $queries Array of meta queries.
* @type string $type Type of meta.
* @type string $primary_table Primary table.
* @type string $primary_id_column Primary column ID.
* @type object $context The main query object.
* }
*/
return apply_filters_ref_array('cn_get_meta_sql', array($sql, $this->queries, $type, $primary_table, $primary_id_column, $context));
}
