Hello, sorry your description is not clear ... why do you use a GROUP BY on product without aggregation function min, max, sum ? where is defined numberOfPremiumDays ? may be using UNION can solve your problem: select numberOfPremiumDays, product_id, premium_price, period_price from product, PremiumDays where occupation_type_id = 1 and numberOfPremiumDays = date_part('day', ('2018-11-05'::timestamp) - ('2018-11-01'::timestamp)) UNION ALL select numberOfPremiumDays, product_id, classic_price, period_price from product1, PremiumDays where occupation_type_id = 1 and numberOfPremiumDays != date_part('day', ('2018-11-05'::timestamp) - ('2018-11-01'::timestamp)) Regards PAscal -- Sent from: http://www.postgresql-archive.org/PostgreSQL-general-f1843780.html