This seems to be working. I had to take a different approach as I had misapprehended GROUP BY completely. SELECT * FROM currency_exchange_rates AS xchg1 WHERE id IN ( SELECT id FROM currency_exchange_rates as xchg2 WHERE xchg1.currency_code_base = xchg2.currency_code_base AND xchg1.currency_code_quote = xchg2.currency_code_quote ORDER BY currency_code_base, currency_code_quote, effective_from DESC LIMIT 1 ) ORDER BY currency_code_base, currency_code_quote, effective_from DESC -- *** E-Mail is NOT a SECURE channel *** James B. Byrne mailto:ByrneJB@xxxxxxxxxxxxx Harte & Lyne Limited http://www.harte-lyne.ca 9 Brockley Drive vox: +1 905 561 1241 Hamilton, Ontario fax: +1 905 561 0757 Canada L8E 3C3 -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general