MYSQL哪种查询更快一点
第一种:
表1:主键为A(20位bigint类型),字段B为字符串(表2的自增ID,多个以“,”分开)
表2:记录
第二种:
记录表,字段A自增,字段B为(20位bigint类型,可重复,加索引)
假设数据都很大,为了拿到某一个20位bigint类型的数据列表,哪种设计查询快?
回复讨论(解决方案)
没看懂,建议贴出表结构,举例说明。
20位bigint,有必要那么大吗?小心 64bit Integer 事件。
20位bigint,有必要那么大吗?小心 64bit Integer 事件。
什么事件呀?没听说过,求解释
是把字符串转成BIGINT的,为了查询快一点
haowen
引用 2 楼 changjay 的回复:20位bigint,有必要那么大吗?小心 64bit Integer 事件。
什么事件呀?没听说过,求解释
是把字符串转成BIGINT的,为了查询快一点
$large_number = 922337203685477580800;
echo $large_number; //9.2233720368548E+20
真的有必要生成那么多位的数字吗?
查询快,一般加index就可以了。INT(11) 11位数字最合理,多了其实也用不上,反而消耗内存资源。
楼上们都歪了...
针对你的问题: 第二种
当然是第二种!
虽然 mysql 提供了 find_in_set 函数可以方便的从逗号分隔的串中提起成员,但函数的执行总是要花点时间的。
哪能比直接读取来的快呢?

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