MYSQL-STRAIGHT_JOIN在此代码中做什么? [英] MYSQL - What does STRAIGHT_JOIN do in this code?

问题描述

STRAIGHT_JOIN在此代码中做什么?

SELECT  STRAIGHT_JOIN ClosingBalance    
FROM   Accounts 
WHERE idAccounts = FidDebit;

解决方案

STRAIGHT_JOIN旨在作为MySQL查询优化器的指令，该表必须按照查询中列出的顺序从左到右连接表.

http://dev.mysql.com/doc/refman/5.0/en/join.html

由于此查询中只有一个表，因此它似乎没有做任何事情.

What does STRAIGHT_JOIN do in this code ?

SELECT  STRAIGHT_JOIN ClosingBalance    
FROM   Accounts 
WHERE idAccounts = FidDebit;

解决方案

STRAIGHT_JOIN is intended as an instruction to the MySQL query optimiser that the tables must be joined from left to right in the order they are listed in the query.

http://dev.mysql.com/doc/refman/5.0/en/join.html

As you only have one table in this query, it wouldn't appear to be doing anything.

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