CREATE FUNCTION dbo.f_splitstr(@SourceSql NVARCHAR(MAX),@StrSeprate VARCHAR(100)) 
 RETURNS @temp TABLE(F1 VARCHAR(100))
 AS
 BEGIN
 DECLARE @ch AS VARCHAR(100)
 SET @SourceSql=@SourceSql+@StrSeprate 
 WHILE(@SourceSql<>'')
     BEGIN
     SET @ch=LEFT(@SourceSql,CHARINDEX(@StrSeprate,@SourceSql,1)-1)
 INSERT @temp VALUES(@ch)
 SET @SourceSql=STUFF(@SourceSql,1,CHARINDEX(@StrSeprate,@SourceSql,1),'')
     END
 RETURN
 END
GO

SELECT * FROM dbo.f_splitstr('a,b,c',',')

SELECT * FROM STRING_SPLIT('a,b,c',',')