php操作MYSQL 语句条件是越多越好还是越少越好呢
问一下
假如现在想update一下
sql1="update table set aa=aa where id=1";
sql2="update table set aa=aa where id=1 and classid=12 and infoid=1";
delete:
sql1="delete from table where id=1";
sql2="delete from table where id=1 and classid=12 and infoid=1";
请问一下update时 sql1和sql2哪个更好些
delete时 sql1和sql2哪个更好些
请说一下原因,谢谢。
------解决方案--------------------
那你就不需要提这个问题了嘛...明显是老鸨(Mysql)给你筛选一下就可以了。要不那些判断条件是做啥用的,我倒...相对来说条件越精确执行的效率越高,结果就精确,当然前提是你的索引,以及SQL语句的写法要正确。很多时候条件没写好反而起反作用。
2,和老鸨子讲一下,身高要170的,上围要80的,把符合这些条件的小姐喊来,然后再从符合这些条件的里面找个叫 如花 的
这个时候老鸨子果断给你找了个如花,在你一番XXOO之后 你发现.... 他奶奶的居然是个变性人! 所以 你的条件一定要弄对。哈哈哈

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