What does this MySQL statement do?

Posted by user198729 on Stack Overflow See other posts from Stack Overflow or by user198729
Published on 2010-05-03T07:27:37Z Indexed on 2010/05/03 7:38 UTC
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mysql

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cross-join

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 .

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