PostgreSQL: percentile_cont vs percentile_disc

percentile_cont(fraction) WITHIN GROUP (ORDER BY sort_expression)

percentile_disc(fraction) WITHIN GROUP (ORDER BY sort_expression) 

percentile_disc returns a value in your set/window, whereas percentile_cont will interpolate

SELECTPERCENTILE_DISC (0.5) WITHIN GROUP (ORDER BY num)
FROM(SELECT*FROMgenerate_series (1, 10) num) A

result: 5

SELECTPERCENTILE_CONT (0.5) WITHIN GROUP (ORDER BY num)
FROM(SELECT*FROMgenerate_series (1, 10) num) A

reslult: 5.5