Expression 1 and 2 aren't identically and won't return the same results.
If you says that you have too many columns and wants therefore to shortcut your expressions I have the impression that you tries to solve challenges within the UI which are better addressed within the script, maybe by transforming (a part of) your data per crosstable into a "normal" data-structure.
Like above hinted I believe that your datamodel isn't really suitable for such a view and a transforming of the structure may simplify the matter - especially if there isn't only one multi-field matching/calculating else several ones.
Nevertheless you may solve it with a set analysis but you need to define it properly - it's regardless if it's done with external variables or maybe a $-sign expansion or just manually written - means you need to define all included fields separately with the wanted values and also applying the intended linking of them respectively the needed operators.
In your case with an extra field to define the fields which should be included such an expression may look like: