ช่วงเวลาการรวมข้อมูลแบบกำหนดเอง

-- Generate 6 month bins covering 2016-01-01 to 2018-06-30

-- Create lower bounds of bins
SELECT generate_series('2016-01-01',  -- First bin lower value
                       ___,  -- Last bin lower value
                       '___'::interval) AS lower,
-- Create upper bounds of bins
       generate_series('2016-07-01',  -- First bin upper value
                       ___,  -- Last bin upper value
                       '___'::interval) AS upper;