To delete If you need to delete all non-system functions in TSQL. We need to look against the sysobjects and looking for the type value under 'FN', 'IF', 'TF', 'FS', and 'FT'.
Here is the full snippet TSQL query to delete user functions in the SQL Server.
DECLARE @functionName VARCHAR(128) DECLARE @SQL VARCHAR(500) SELECT @functionName = ( SELECT TOP 1 [name] FROM sysobjects WHERE [type] IN (N'FN', N'IF', N'TF', N'FS', N'FT') AND category = 0 ORDER BY [name] ) WHILE @functionName IS NOT NULL BEGIN SELECT @SQL = 'DROP FUNCTION [dbo].[' + RTRIM(@functionName) +']' EXEC (@SQL) PRINT 'Deleted Function: ' + @functionName SELECT @functionName = ( SELECT TOP 1 [name] FROM sysobjects WHERE [type] IN (N'FN', N'IF', N'TF', N'FS', N'FT') AND category = 0 AND [name] > @functionName ORDER BY [name] ) END GO
The way above script works by finding the first top function name and set it to a variable. Then it performs a while loop by checking against the variable name value. Inside the looping, it will perform a deleting against the function name set in the variable and perform another finding of the first top function record. if it finds it, it will then set it back to the variable again. The while loop will keep looping until the function name is no longer found.