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MySQL部分 #2639

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Xuxiusheng opened this issue Mar 14, 2025 · 1 comment

Xuxiusheng commented Mar 14, 2025

在MySQL的NULL与“”对比的那一部分写到“”是不占用空间的，但是

如果是char字段，需要填充到指定长度，是占用空间的
如果是varchar字段，其实和NULL一样是有隐藏字段来标识字段实际长度的，这个标识字段为1或2个字节，并且每个变长字段都会有一个
所以，综上的话，其实“”字符串实际上是占用空间的

Owner

Snailclimb commented Mar 14, 2025

在MySQL的NULL与“”对比的那一部分写到“”是不占用空间的，但是

如果是char字段，需要填充到指定长度，是占用空间的

如果是varchar字段，其实和NULL一样是有隐藏字段来标识字段实际长度的，这个标识字段为1或2个字节，并且每个变长字段都会有一个
所以，综上的话，其实“”字符串实际上是占用空间的

不好意思，这里我前几个月就已经修改了，但还未同步到网站上去：

Snailclimb closed this as completed

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