变量数据库名称 [英] variable database name

问题描述

MySQL中是否可以将数据库名称放入变量中? 例如，当我有一个名为"db1"的数据库时，我可以这样做吗?

Is there any way in MySQL to put the name of the database into a variable? For example, when I have a database called 'db1', can I do something like this:

set @db= 'db1';
select * from @db.mytable;

还有一个我想做的例子:

There is another example of what I want to do:

set @dbfrom= 'db1';
set @dbto= 'db2';
insert into @dbto.mytable (col1,col2,col3) select col2,col1,col3 from @dbfrom.mytable;

推荐答案

是相当费力的.

SET @db = 'db1';
SET @q = CONCAT('SELECT * FROM ', @db, '.mycol');
PREPARE stmt FROM @q;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

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