为什么您不应该多次使用mysql_fetch_assoc? [英] Why you should not use mysql_fetch_assoc more than 1 time?

问题描述

有人说您不应该多次使用mysql_fetch_assoc，为什么?

Some people say you should not use mysql_fetch_assoc more than one time, why is that?

例如:我想显示两个表，一个与付费会员的用户一起显示，另一个与不付费的用户一起显示，因此我没有查询2次数据库，而是一次查询了两种类型的用户的$result变量，然后我运行循环mysql_fetch_assoc，看看是否list['membership'] = 'paid'然后回声...

e.g.: I want to display two tables one with users who paid for membership, other with users who did not, so instead of querying database 2 times I query it one time and get $result variable with both types of users then I run loop mysql_fetch_assoc and see if list['membership'] = 'paid' then echo ...

第二次，我循环循环mysql_fetch_assoc，看看是否list['membership'] = 'free'然后回显...

Second time I loop loop mysql_fetch_assoc and see if list['membership'] = 'free' then echo ...

考虑到我获得的注册和未注册用户数量相等，哪些资源使用较少?

What uses less resources considering I got about equal amount of users who registered and unregistered.

推荐答案

将您的查询结果集视为香肠，并将mysql_fetch_assoc()当作刀将香肠切成薄片.每次取一行时，都会切掉另一根香肠，它永远都是新的香肠.您不能去切掉先前切过的一块，因为它已经被吃掉了.

Think of your query result set as a sausage, and mysql_fetch_assoc() as a knife that slices off a piece of that sausage. Every time you fetch a row, another piece of sausage is cut off, and it's always a NEW piece of sausage. You can't go and cut off a previously cut piece, because it's been eaten already.

这篇关于为什么您不应该多次使用mysql_fetch_assoc?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！