Get the value at runtime

Question

Can anybody tell me how i can do this?

declare @test varchar(20)
set @test ='DatabaseName'

select b.* from @test.dbo.Table_Name  

Here i am taking database from variable and using it in query.

Shall do this?

Answer 1

declare @test varchar(20)
set @test ='DatabaseName'

declare @SQL nvarchar(max)
set @SQL = 'select b.* from '+quotename(@test)+'.dbo.Table_Name as b'

exec (@SQL)

Answer 2

Make use of Exec command or Sp_executesql because you are building dynamic query.

sp_executesql (Transact-SQL)