SQL Server: How to use a database name as a parameter in a stored procedure?

Question

How can I do a join on tables of 2 different db in same domain like

SET DBname = \"sample\"
SELECT *
FROM Table1
INNER JOIN DBname.Tab         


        

Answer 1

You have to use dynamic sql:

@DBname = 'sample';
declare @sql nvarchar(max);

set @sql = '
SELECT *
FROM Table1 INNER JOIN
     @DBname.table2
     On Table1.key = Table2.Key';

set @sql = replace(@sql, '@DBname', @DBname);

exec sp_executesql @sql;

Databases in general -- and SQL Server in particular -- do not allow parameters to represent database names, schema names, table names, or column names.