Cumulative count cut with postgresql -


is there possibility realize cumulative count cut of 2.0 - 98.0% in postgresql?

that means select data range set 2% until 98%.

i suggest window function ntile() in subquery:

select *  (    select *, ntile(50) on (order ts) part      tbl     ts >= $start    ,    ts <  $end    ) sub part not in (1, 50);

ts being date column.

ntile() assigns integer numbers rows dividing them number of partitions specified. per documentation:

integer ranging 1 argument value, dividing partition equally possible

by using 50 partitions first partition matches first 2 % closely possible , last last 2 % (> 98%).

note, if there less 50 rows assigned numbers never go 50. in case first row trimmed not last. since first , last 2 % not defined such low number of rows may considered correct or incorrect. check total number of rows , adapt needs. instance trimming last row, too. or none @ all.


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