I already have used these ways, but when I have value in both, the command returns me only the value of one.

You can try using gold | (or)  "selectdb sum(field) of "table" u_where (key = "1+|2") to value" or maybe "selectdb sum(field) of "table" u_where (key = $syntax("1+|2")) to value"   failing that, it's back to go old OR.  "selectdb sum(field) of "table" u_where ((key = 1 or key = 2)) to value"

I see no other option than: "selectdb sum(field) of "table" u_where (key = 1 | key = 2) to value" Maybe it would be nice to have the "where" clause available on the selectdb and not just the "u_where"