Ignore all selections except some specific fields using Set Analysis

Hello.

As far as I was designing apps for QV - I've found a great need in some charts to ignore all possible selections except some specific fields.

Exploring possible ways to do so - the first my decision was to use dollar-sign expression inside my Set Analysis which could make an exception like next:
(Let's imagine that in my scheme there are fields [Stock], [Manager], [Date], [City], [Client] and [Amount])

`sum({1<[Stock]={'Stock 1','Stock 3'}>} Amount)`

If I selected only 'Stock 1' and 'Stock 3' in field [Stock] - and this way has shown it's profit - you can get it using this expression:

```sum({1<[Stock]=\$(=if(GetSelectedCount([Stock], true( ))>0,'{' & chr(39) & GetFieldSelections([Stock],chr(39) & ',' & chr(39),GetSelectedCount([Stock], true( ))) & chr(39) & '}', ''))>} Amount)
```

If you need two, three, or more fields - you can simply add such code for every field into Set Analysis:

```sum({1<[Stock]=\$(=if(GetSelectedCount([Stock], true( ))>0,'{' & chr(39) & GetFieldSelections([Stock],chr(39) & ',' & chr(39),GetSelectedCount([Stock], true( ))) & chr(39) & '}', '')),[Manager]=\$(=if(GetSelectedCount([Manager], true( ))>0,'{' & chr(39) & GetFieldSelections([Manager],chr(39) & ',' & chr(39),GetSelectedCount([Manager], true( ))) & chr(39) & '}', ''))>} Amount)
```

But what if you have a field containing hundreds of records? Can you imagine what will be the length of your expression? That's why I started to discover another way to do that. I've thought - what if I use not "1" Set, but "\$" Set in my expression and write in it all the fields that must be ignored, something like that:

```sum({\$<[Date]=,[City]=,[Client]=,[Amount]=>} Amount)
```

So, using such expression - I get that all the fields except for [Stock] and [Manager] are ignored, but how car I make it automatic? Sure using our lovely dollar-sign expressions and system field \$Field:

```sum({\$<[\$(=Concat({1<\$Field-={'Stock','Manager'}>}distinct \$Field,']=,[')&']=')>} Amount)
```

where inside the set analysis of Concat function you can insert fields that you are interested in (by the way - there you can insert even tables using system field \$Table and others).