May I clarify the ideas being discussed so far, perhaps with a view to make a relevant proposal. My apologies if I get anything wrong or go too far.
As I understand it the proposal is to supplement the syntax to something like: INSERT INTO table (a, b, c) VALUES ((1,2,3), (4,5,6), ...) WITH ORDINALITY RETURNING table.id, ordinality ; The meaning of which is to adjoin an ordinality column to the output reflecting the declaration order in the values clause. So an output of (not necessarily in any order): (1001, 1) (1003, 2) means that table.id = 1001 was assigned to the inserted row from tuple (1,2,3) (from VALUES, because that table.id is associated to ordinality = 1) and table.id = 1003 was assigned to the inserted row from tuple (4,5,6). The output being ordered as determined by the internals of query execution (not necessarily the one shown). Is that correct? I presume (although, not quite so clear) that one would have: INSERT INTO table (a, b, c) SELECT a_val, b_val, c_val FROM joined_tables WHERE some_condition ORDER BY something_relevant WITH ORDINALITY RETURNING table.id, ordinality ; The meaning being very much as before replacing 'declaration order' by 'row order of the SELECT statement as defined by the ORDER BY clause'; so pretty much like a row_number() but in the output of the RETURNING clause (and without an OVER modification). I added the ORDER BY clause as I don't really see what this would mean without it; but this (presumably) does not affect output order only the order of the incoming rows (and hence the generation of the ordinality output). Is that correct? Might there be a natural syntax to label the 'ordinality' output column? Perhaps something like: ... WITH ORDINALITY (col_name) RETURNING table.id, col_name ; I don't want to clash with the syntax for Table Functions. Is it a step too far to propose allowing an additional ORDER BY clause after the RETURNING clause (a specific declaration for the query execution to assign cpu cycles; especially if the WITH ORDINALITY is not tied to output order)? Personally, I didn't see Frederico's comment as anything to do with order; just how one could output additional values in the RETURNING clause (namely, v.num from a subexpression of the SELECT but in whatever order it comes). On the other hand, that seems a lot more complicated to me because it is not an expression in the overall SELECT feeding the INSERT, whereas the WITH ORDINALITY is a specific declaration to match input order with output order by inserting a counter. Apologies, if I have misunderstood or invented something that's not possible!
