在MySql 5.1版本上使用EXCEPT运算符 [英] Using EXCEPT operator on MySql 5.1 version

问题描述

我的服务器上有5.1 MySQL版本.我正在尝试执行以下查询:

I have 5.1 MySQL version on my server. I am trying to perform this query:

SELECT File_Name
FROM Words_DB
WHERE Word_Name=" . $element . "
EXCEPT 
SELECT File_Name 
FROM Files_DB 
WHERE Display=0

我遇到错误:

错误:您的SQL语法有错误；在第4行的'EXCEPT SELECT File_Name FROM Files_DB WHERE Display = 0'附近使用相应的语法，查看与您的MySQL服务器版本相对应的手册

Error: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'EXCEPT SELECT File_Name FROM Files_DB WHERE Display=0' at line 4

有人可以告诉我如何以其他形式执行此查询吗?

Can someone tell me how can i perform this query in an alternative form?

谢谢，最大.

推荐答案

据我所知，MySQL不支持EXCEPT运算符.尝试以下方法:

As far as I know MySQL does not support theEXCEPToperator. Try this instead:

SELECT File_Name
FROM Words_DB
WHERE Word_Name=" . $element . "
AND File_Name NOT IN (
  SELECT File_Name 
  FROM Files_DB 
  WHERE Display=0
)

您还可以使用相关的NOT EXISTS或a LEFT JOIN.由于我使用的不是MySQL太多，所以我不能说哪个性能最好.

You could also use either a correlatedNOT EXISTSor aLEFT JOIN. As I don't use MySQL much I can't say which performs best.

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