Question

Find difference between find first and can-find in progress 4gl

Answer 1

You should rarely, if ever, use either of these. Both of them are misleading and dangerous.

FOR FIRST is especially nasty -- it finds the record before any specified sorting using whatever index the index selection rules result in. A BY clause will be ignored.

If you are dealing with an ordered set of data use OPEN QUERY or FOR EACH with an appropriate BY clause.

If you are dealing with a unique record use FIND without the FIRST but with an appropriately selective WHERE clause that is supported by an index.