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mysql自联结

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Release: 2016-06-07 16:37:36
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mysql的 自联结 的处理速度比子查询快了很多。所以自联结还是有必要学习的。 普通的s ql子查询语句 SELECT `id`,`bic` FROM `biao` WHERE `id`=(SELECT `id` FROM `biao` WHERE `id`='9696e'); mysql的自联结sql语句 SELECT `id`,`bic` FROM `biao` AS a, `b

mysql的自联结的处理速度比子查询快了很多。所以自联结还是有必要学习的。
普通的sql子查询语句

SELECT `id`,`bic` FROM `biao` WHERE `id`=(SELECT `id` FROM `biao` WHERE `id`='9696e');
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mysql的自联结sql语句

SELECT `id`,`bic` FROM `biao` AS a, `biao` AS b WHERE a.id=b.id AND b.id='9696e';
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自联结的sql语句看起来也清爽优美。

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