MySQL如果存在，则插入或执行其他操作 [英] MySQL If exsists insert into or else do something else

问题描述

在将条件插入MySQL时遇到一些困难.我一直在尝试创建一个查询，该查询将遍历所有标题为email的列，如果存在，我想执行以下操作: 如果存在电子邮件，我希望它使列的现有值正确，并向其中添加php变量$ correct.但是，如果电子邮件不存在，那么我希望它向$ mail列中添加一个值为$ email的新记录，并向right列中添加$ correct.任何帮助将不胜感激.
这是我所拥有但不起作用的内容:

I'm having some difficulty putting a conditional into MySQL. I've been trying to create a query that will go through all of the column titled email and if it exists I want to do something like this: If an email exists I want it to take the existing value of the column correct and add the php variable $correct to it. But if an email does not exist then I want it to add a new record with the values $email into the column email and $correct into column correct. Any help would be greatly appreciated.
Here's what I have and does not work:

IF  (SELECT * FROM facebookqs WHERE email = '$email' > 0)
UPDATE facebookqs SET correct = correct + '$correct' where email ='$email' 
Else
Insert into facebookqs (email, correct) VALUES ('$email', '$correct')

推荐答案

假设email具有UNIQUE约束，则应使用

Assuming email has a UNIQUE constraint, you should use INSERT ... ON DUPLICATE KEY UPDATE

INSERT INTO facebookqs (email, correct) VALUES ('$email', '$correct')
ON DUPLICATE KEY UPDATE correct = correct + '$correct'

另请参阅我对其他堆栈溢出问题的回答:

See also my answer for this other Stack Overflow question: INSERT IGNORE vs INSERT … ON DUPLICATE KEY UPDATE

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