Variable to select database in SQL query

If I want use a variable in the FROM clause of a SQL query I [need to use dynamic SQL.](https://stackoverflow.com/a/41250925/2112418) Which might be a pain if the query is long and complex. There are few different ways of running a query from a database you are not currently connected to. The two methods I use most often are these.. Select * from msdb..sysjobs_view or USE MSDB Select * from sysjobs_view If you start on the master database both of the above will give you the same results. When I put these both into dynamic SQL one works and the other does not Starting from master, this works DECLARE @DBN SYSNAME SET @DBN = 'msdb' DECLARE @Sql NVARCHAR(MAX) SET @Sql = N'Select * from ' + @DBN + '..sysjobs_view' EXEC (@Sql) But this does not DECLARE @DBN SYSNAME SET @DBN = 'msdb' DECLARE @Sql NVARCHAR(MAX) SET @Sql = N'USE ' + @DBN EXEC (@Sql) Select * from sysjobs_view I get the error > Msg 156, Level 15, State 1, Line 14 > Incorrect syntax near the keyword 'EXEC'. My reason for this: One line of dynamic SQL in big complex query is going to be less painful to code than trying to turn the whole query into dynamic SQL. My question here is just about why its not working with the USE clause. Why can't I use dynamic SQL with the [USE clause](https://learn.microsoft.com/en-us/sql/t-sql/language-elements/use-transact-sql?view=sql-server-ver15) to change the database context? NOTE: The below does work and would be easy to code. But my question about why remains. DECLARE @DBN SYSNAME SET @DBN = 'msdb' DECLARE @Sql NVARCHAR(MAX) SET @Sql = N'USE ' + @DBN +' Select * from sysjobs_view ' EXEC (@Sql)