mysql-查询内的查询 [英] mysql - query inside a query

问题描述

如何执行以下操作: (我正在使用mysql-phpmyadmin)

How is it possible to do the following : (i am using mysql - phpmyadmin )

此查询返回一个表名:

Select table_name from Table1 where id = 1

我想在另一个查询中使用它，例如:

I want to use it inside another query , like :

select val from (Select table_name from Table1 where id = 1)

但是这种确定是行不通的，并且由于phpmyadmin不支持调用存储过程，因此有什么可能的解决方案?

but this sure does not work, and since phpmyadmin does not support calling stored procedures, could there be any possible solution for this ?

推荐答案

您不能在单个SQL语句中真正做到这一点.

You cannot really do it in a single SQL statement.

您试图将data(字段值)用作metadata(表名)，而SQL不允许这样做.

You are trying to use data (field value) as metadata (table name), and SQL does not allow this.

您可以将其分为两个语句，也可以在存储过程中写入动态SQL.请注意，并非所有的客户端层都支持从存储过程返回结果集.

You could break it in two statements or write dynamic SQL in a stored procedure. Note that not all client layers support returning resultsets from stored procedures.

这篇关于mysql-查询内的查询的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！