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mysql> SELECT * FROM tag -> JOIN tag_post ON tag_post.tag_id=tag.id -> JOIN post ON tag_post.post_id=post.id -> WHERE tag.tag='mysql';
可以分解成:
mysql> SELECT * FROM tag_post WHERE tag_id=1'; mysql> SELECT * FROM tag_post WHERE tag_id=1234; mysql> SELECT * FROM post WHERE post.id in (123,456,567,9098)
MySQL执行一个查询的过程:
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