Re: pgsql-function

On Tue, Apr 14, 2015 at 03:39:38AM -0700, Rishi Ranjan wrote:
> i have data like below and where ap_key is same for two different
> first_occurence column . here i need to write a function which can
> calculate the difference of two timestamp values for a Ap_Key and then with
> difference it should multiply the severity
>
> AAA_key AP_KEY FIRSTOCCURRENCE SEVERITY
> 111 418 3/4/2014 0:00 5
> 111 418 3/4/2014 0:05 0
> 112 12 3/4/2014 0:40 4
> 112 12 3/4/2014 0:45 0
> 113 13 3/4/2014 1:05 3
> 113 13 3/4/2014 1:10 0
> 114 114 3/4/2014 1:30 2
> 114 114 3/4/2014 1:35 0
> 115 35 3/4/2014 2:10 1
> 115 35 3/4/2014 2:15 0
> 116 116 3/4/2014 10:14 4
> 116 116 3/4/2014 10:19 0
> 117 127 3/4/2014 11:45 3
> 117 127 3/4/2014 11:49 0
> 118 118 3/4/2014 12:10 2
> 118 118 3/4/2014 12:14 0
> 119 19 3/4/2014 12:35 1
> 119 19 3/4/2014 12:39 0
> 119 120 3/4/2014 0:00 4
> 119 120 3/4/2014 1:40 0

Given this data, why don't you simply:

select
AAA_key,
AP_KEY,
max(SEVERITY),
max(FIRSTOCCURRENCE) - min(FIRSTOCCURRENCE)
from
table
group by
AAA_key,
AP_KEY;

and then do whatever math you need on severity or FIRSTOCCURRENCE
differences.

depesz