Normally IN is used with one value:
SELECT * FROM data WHERE f1 IN (<subquery>)
It is possible to use it with multiple values:
SELECT * FROM data WHERE f1 IN (<subquery>) OR f2 IN (<subquery>);
But can I remove duplication, something like:
SELECT * FROM data WHERE ANY(f1, f1) IN (<subquery>)
I tried to use CTE, but it also require subquery.