aggregate function to return true if value exists

Question

I've got some SQL query which returns the sum of certain fields, and there's a flag column associated with these values, either 'Y' or 'N'.

Is there an aggregate function which will return a true/false on this flag column if any one record contains a 'Y'?

Answer 1

You could wrap conditional aggregation inside a CASE expression:

CASE
    WHEN COUNT(CASE WHEN column = 'Y' THEN 1 END) > 0 THEN 'true'
    ELSE 'false'
END

Answer 2

select nvl(max(1),0) from your_table
where column = 'Y'