Join between tables in two different databases?

MysqlSqlJoin

Mysql Problem Overview

In MySQL, I have two different databases -- let's call them A and B.

Is it possible to perform a join between a table that is in database A, to a table that is in database B?

Mysql Solutions

Solution 1 - Mysql

Yes, assuming the account has appropriate permissions you can use:

SELECT <...>
FROM A.table1 t1 JOIN B.table2 t2 ON t2.column2 = t1.column1;

You just need to prefix the table reference with the name of the database it resides in.

Solution 2 - Mysql

SELECT <...> 
FROM A.tableA JOIN B.tableB

Solution 3 - Mysql

SELECT *
FROM A.tableA JOIN B.tableB

or

SELECT *
  FROM A.tableA JOIN B.tableB
  ON A.tableA.id = B.tableB.a_id;

Solution 4 - Mysql

SELECT <...>
FROM A.table1 t1 JOIN B.table2 t2 ON t2.column2 = t1.column1;

Just make sure that in the SELECT line you specify which table columns you are using, either by full reference, or by alias. Any of the following will work:

SELECT *
SELECT t1.*,t2.column2
SELECT A.table1.column1, t2.*
etc.
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Content TypeOriginal AuthorOriginal Content on Stackoverflow
Questionuser3262424View Question on Stackoverflow
Solution 1 - MysqlOMG PoniesView Answer on Stackoverflow
Solution 2 - MysqlSenthilView Answer on Stackoverflow
Solution 3 - MysqlKalaivani MView Answer on Stackoverflow
Solution 4 - MysqlNoel SwansonView Answer on Stackoverflow