使用来自同一MySQL Server的不同数据库的两个表中的联接执行查询

Question

I need to execute a Query(Select only) with join of two tables from different database of same server.

Eg query will be similar to:

SELECT * FROM DB1.tbl_a LEFT JOIN DB2.tbl_b ON   DB1.tbl_a.fieldX = DB2.tbl_b.fieldY WHERE ....

Where tbl_a , tbl_b are 2 tables from 2 different database DB1 , DB2 respectively

How to do that? How can I connect to MySQL server without specifying the database in the connection string but in sql query Using C# .?

Answer 1

Actually this question has already been answered, here is the answer :

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

SELECT ...
  FROM A.table t1
  JOIN B.table2 t2 ON t2.column = t1.col

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

Answer 2

I need to execute a Query(Select only) with join of two tables from different database of same server.

For this SQL User have access on both Databases.

Query will be like this:

SELECT * FROM [DB1].[dbo].[tbl_a] T1 LEFT JOIN [DB2].[dbo].[tbl_b] T2 ON T1.fieldX = T2.fieldY WHERE ....