What does this MySQL statement do?
- by user198729
INSERT IGNORE INTO `PREFIX_tab_lang` (`id_tab`, `id_lang`, `name`)
(SELECT `id_tab`, id_lang, (SELECT tl.`name`
FROM `PREFIX_tab_lang` tl
WHERE tl.`id_lang` = (SELECT c.`value`
FROM `PREFIX_configuration` c
WHERE c.`name` = 'PS_LANG_DEFAULT' LIMIT 1) AND tl.`id_tab`=`PREFIX_tab`.`id_tab`)
FROM `PREFIX_lang` CROSS JOIN `PREFIX_tab`);
It's from an opensource project,and no documentation available.
Especially,what does cross-join mean? I've only used join/left join .