Database: Add support for SET STATEMENT in wpdb::get_table_from_query().

MariaDB supports setting various parameters for queries. This commit ensures that `wpdb` can properly retrieve the table name from such queries.

Reference: [https://mariadb.com/docs/server/reference/sql-statements/administrative-sql-statements/set-commands/set-statement MariaDB Documentation: SET STATEMENT].

Follow-up to [30345].

Props dd32.
Fixes #63777.

git-svn-id: https://develop.svn.wordpress.org/trunk@60622 602fd350-edb4-49c9-b593-d223f7449a82

Author: SergeyBiryukov

src/wp-includes/class-wpdb.php

@@ -3803,6 +3803,9 @@ protected function get_table_from_query( $query ) {
 		// Strip everything between parentheses except nested selects.
 		$query = preg_replace( '/\((?!\s*select)[^(]*?\)/is', '()', $query );
 
+		// Strip any leading SET STATEMENT statements.
+		$query = preg_replace( '/^SET STATEMENT.+?\sFOR\s+/is', '', $query );
+
 		// Quickly match most common queries.
 		if ( preg_match(
 			'/^\s*(?:'

tests/phpunit/tests/db.php

@@ -850,6 +850,9 @@ public function data_get_table_from_query() {
 
 			// @ticket 32763
 			'SELECT ' . str_repeat( 'a', 10000 ) . " FROM (SELECT * FROM $table) as subquery",
+
+			// @ticket 63777
+			"SET STATEMENT max_statement_time=1 FOR SELECT * FROM $table",
 		);
 
 		$querycount = count( $queries );