本文介绍了MYSQL查询使用变量作为LEFT JOIN中的表名的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
SELECT var1,var2,var3,table_name
FROM table1 LEFT JOIN table_name on var3=table_name.id
意思是我想根据table1
中table_name
的值来动态离开联接表,因为var3
是从那里取来的.
Meaning I want to dynamically left join table, depending on value of table_name
from table1
, since var3
is taken from there.
但是上面的查询结果是
我对mysql限制有误吗?
My mistake of mysql limitation?
推荐答案
表名和列名在SQL查询中不能是动态的.因此,您必须使用2个查询或存储过程以编程方式应用逻辑,请参见此处的示例: http://forums.mysql.com/read.php?98,126506,126598#msg-126598
Table names, as well as column names, can't be dynamic in an SQL query. So you have to apply your logic programmatically, using 2 queries, or with a stored procedure, see an example here: http://forums.mysql.com/read.php?98,126506,126598#msg-126598
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