Convert TIMESTAMP difference column data to string format - sql

Question

From my view, I am getting a column with value like '0 0:0:0.343009' which shows the difference between two timestamps, to millisecond precision.
I would like to show them as a string like 343 milliseconds or other value but should be a millisecond conversion.
I had similar post in the past but that time column was a DATE datatype, and this time it is a TIMESTAMP. I am using the FLOOR function to change the output to a numeric value to show a more user friendly result.
I used sample query to find a difference of dates. Here created_time is a TIMESTAMP datatype:
select msg_guid,
(max(case when payload_type = 1 then created_time end) -
(case when max(case when payload_type = 2 then created_time end) <>
trunc(max(case when payload_type = 2 then created_time end))
then max(case when payload_type = 2 then created_time end)
when max(case when payload_type = 3 then created_time end) <>
trunc(max(case when payload_type = 3 then created_time end))
then max(case when payload_type = 3 then created_time end)
end)
) as diff
from table t
group by msg_guid;

Answer 1

When you add or subtract timestamps, the result is an interval, not another timestamp. You can use the extract function to pull the components out of that. If you value is always going to be sub-second you can just extract the seconds, and multiply by a thousand to get the milliseconds:
with t as (
select 1 as msg_guid,
interval '0 0:0:0.343009' day to second as diff
from dual
)
select trunc(extract (second from diff) * 1000)
from t;
TRUNC(EXTRACT(SECONDFROMDIFF)*1000)
-----------------------------------
343
Here your real query would take the place of the dummy CTE I used with an interval literal.
If the interval might be more than a second then you would presumably want to get the entire value in milliseconds, so you'd need to extract all the elements and add them together, multiplying each based on what they represent - so a full day would be 86400000 milliseconds etc.; the plain elements would come out like:
column diff format a25
with t as (
select 1 as msg_guid,
systimestamp - trunc(systimestamp) as diff
from dual
)
select diff,
extract (day from diff) as dd,
extract (hour from diff) as hh,
extract (minute from diff) as mi,
extract (second from diff) as ss
from t;
DIFF DD HH MI SS
---------------------- ---------- ---------- ---------- ----------
0 9:13:26.150627 0 9 13 26.150627
And you'd combine them like:
with t as (
select 1 as msg_guid,
systimestamp - trunc(systimestamp) as diff
from dual
)
select diff,
trunc(1000 * (
extract (day from diff) * (60*60*24)
+ extract (hour from diff) * (60*60)
+ extract (minute from diff) * 60
+ extract (second from diff)
)) as milliseconds
from t;
DIFF MILLISECONDS
---------------------- ------------
0 9:13:27.650365 33207650
But based on your previous question, maybe you want it as a string, as the separate components:
with t as (
select 1 as msg_guid,
systimestamp - trunc(systimestamp) as diff
from dual
)
select diff,
extract (day from diff) || ' DAYS '
|| extract (hour from diff) || ' HOURS '
|| extract (minute from diff) || ' MINUTES '
|| trunc(extract (second from diff)) || ' SECONDS '
|| (trunc(extract (second from diff) * 1000)
- (trunc(extract (second from diff)) * 1000)) || ' MILLISECONDS'
as text
from t;
DIFF TEXT
---------------------- -------------------------------------------------------
0 9:43:38.896007 0 DAYS 9 HOURS 43 MINUTES 38 SECONDS 896 MILLISECONDS
SQL Fiddle based on your sample data, sort of, and with the time calculation reversed so the value is positive.