The problem is that trying to convert the 26 character string '45\Behandlet-45' to INT delivers NULL. You need to hand the the right string to TRY_CONVERT. It isn't clear which of the two occurrences of '45'in the original string you want (or even whether it matters which you get - if the numeric is repeated twice in each sting you want to do this with, as it is in this example, it doesn't matter which string you get); if it's the first one, you can correct the length using another call of PATINDEX to find the first not --9 character after the start you've selected, and then doing some arithmetic; if you want something that's at the end of the string, there are suggestions earlier in this topic for finding the right start position and the length you use in the call to substring can be the length of the whole original string since you are going to the end.