Microsoft® SQL Server 2012 Unleashed

Rewriting Stored Procedures as Functions

In releases of SQL Server prior to SQL Server 2000, if you wanted to do custom processing within SQL code, your only real option was to create stored procedures to do things that often would have worked much better as functions. For example, you couldn’t use the result set of a stored procedure in a WHERE clause or to return a value as a column in a select list. Using a stored procedure to perform calculations on columns in a result set often required using a cursor to step through each row in a result set and pass the column values fetched, one at a time, to the stored procedure as parameters. This procedure then typically returned the computed value via an output parameter, which had to be mapped to ...