Set analysis: Two Fields in a expression

[#1]

Hello:

I want that, an expression with the set analysis, don't apply the filters of two fields.

I want to do something like that:

SUM({$<Field1, Field2>} Sales)

or

SUM({$<Field1>}{$<Field2>} Sales)

But this expressions don't work

I know that with only one field, the expression goes well:

SUM({$<Field3>} Sales)

Thank you for your help

[Roop · Accepted solution]

sum( {$<Field= {Value1, Value2}>} Sales )

or

sum( {$<Field1= {Value1}, Field2= {Value2}>} Sales )

[#3]

Thank You Rupert;

I don't know how I try before, but reading your answer I tried another time this expression and its works :

SUM({$<Field1, Field2>} Sales)

Thanks,

Fernando