可以减少MySQL中的变量吗? [英] Is it possible to decrement a variable in MySQL?

问题描述

我想在每次运行UPDATE查询时将MySQL表中的变量减一.

I'm wanting to decrement a variable in a MySQL table by one everytime an UPDATE query is ran.

我所拥有的是这个，它不起作用:

What I have is this, which isn't working:

UPDATE forum SET replys = reply-- WHERE fid = '$id'

这是否有可能，还是我必须先运行SELECT并先获取该值，然后递减该值，然后将新值插入UPDATE查询中?

Is this possible in any way, or am I going to have to run a SELECT and get the value first, decrement it, and then insert the new value into the UPDATE query?

推荐答案

UPDATE forum SET replys = reply - 1 WHERE fid = '$id'

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