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MYSQL SET类型字段的SQL操作知识_MySQL

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Jun 01, 2016 pm 01:41 PM

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MYSQL SET类型字段的SQL操作知识 [php] `mark` set('index','best','hot') 用的人少，懂的人也少，找了很久，总算凑齐了一套知识点看上面的结构，MYSQL不傻，会存index吗，不会，存的是数字SET字段是利用二进制数字来一一对应你设置的值，比如index，排在第0位，那么2的零次方等于1 [php] update from table SET mark=1 [php] update from table SET mark='index' 上面两个效果是一样的。接着问题就来了，就像织梦那样，如果我想将一篇文章添加一个热门，但是不想删除其它标识在呢么办，或者我就想删除一个标识，我也不知道以前有什么标识。以下是添加标识[php] update from table SET mark=mark |1|2 不要问我为什么用|这个东东，上面的意思是添加index、best两个标识，如果只添加hot标识，写成|4就可以了下面是删除标识[php] update from table SET mark=mark &~4&~1 好了，我先说了更新，下面说查询[php] SELECT * FROM table WHERE FIND_IN_SET('hot',mark) 这个是最简单的查询方法，也可以用hot所在位置的二进制数4来替代查询，效率是一样的也可以这么写：[php] SELECT * FROM table WHERE mark & 1 作者 longxuu bitsCN.com

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