Hier eine Lösung
declare @NameVorname nvarchar(50), @Name nvarchar(25) , @Vorname nvarchar(25), @VornameName nvarchar(50)
set @NameVorname = 'Mustermann, Max'
set @Name = substring(@NameVorname,1,CHARINDEX ( ',',@NameVorname ,1 )-1)
set @VorName = substring(@NameVorname,CHARINDEX ( ',',@NameVorname ,1 )+2, len(@NameVorname) -CHARINDEX ( ',',@NameVorname ,1 ))
set @VornameName=@Vorname+' '+ @Name
print @NameVorname
Print '"' + @name + '"'
Print '"' + @Vorname + '"'
print @VornameName
Gruss Walhai