In Oracle, is there a function that calculates the difference between two Dates? - oracle

Question

In Oracle, is there a function that calculates the difference between two Dates? If not, is a way to display the difference between two dates in hours and minutes?
Query:
SELECT Round(max((EndDate - StartDate ) * 24), 2) as MaximumScheduleTime,
Round(min((EndDate - StartDate) * 24), 2) as MinimumScheduleTime,
Round(avg((EndDate - StartDate) * 24), 2) as AveragegScheduleTime
FROM table1

Answer 1

You can subtract two dates in Oracle. The result is a FLOAT which represents the number of days between the two dates. You can do simple arithmetic on the fractional part to calculate the hours, minutes and seconds.
Here's an example:
SELECT TO_DATE('2000/01/02:12:00:00PM', 'yyyy/mm/dd:hh:mi:ssam')-TO_DATE('2000/01/01:12:00:00AM', 'yyyy/mm/dd:hh:mi:ssam') DAYS FROM DUAL
Results in: 1.5

Answer 2

You can use these functions :
1) EXTRACT(element FROM temporal_value)
2) NUMTOYMINTERVAL (n, unit)
3) NUMTODSINTERVAL (n, unit).
For example :
SELECT EXTRACT(DAY FROM NUMTODSINTERVAL(end_time - start_time, 'DAY'))
|| ' days ' ||
EXTRACT(HOUR FROM NUMTODSINTERVAL(end_time - start_time, 'DAY'))
||':'||
EXTRACT(MINUTE FROM NUMTODSINTERVAL(end_time - start_time, 'DAY'))
||':'||
EXTRACT(SECOND FROM NUMTODSINTERVAL(end_time - start_time, 'DAY'))
"Lead Time"
FROM table;

Answer 3

With Oracle Dates, this is pretty
trivial, you can get either TOTAL
(days, hours, minutes, seconds)
between 2 dates simply by subtracting
them or with a little mod'ing you can
get Days/Hours/Minutes/Seconds
between.
http://asktom.oracle.com/tkyte/Misc/DateDiff.html
Also, from the above link:
If you really want 'datediff' in your
database, you can just do something
like this:
SQL> create or replace function datediff( p_what in varchar2,
2 p_d1 in date,
3 p_d2 in date ) return number
4 as
5 l_result number;
6 begin
7 select (p_d2-p_d1) *
8 decode( upper(p_what),
9 'SS', 24*60*60, 'MI', 24*60, 'HH', 24, NULL )
10 into l_result from dual;
11
11 return l_result;
12 end;
13 /
Function created

Answer 4

Q: In Oracle, is there a function that calculates the difference between two Dates?
Just subtract one date expression from another to get the difference expressed as a number of days. The integer portion is the number of whole days, the fractional portion is the fraction of a day. Simple arithmetic after that, multiply by 24 to get hours.
Q: If not, is a way to display the difference between two dates in hours and minutes?
It's just a matter of expressing the duration as whole hours and remainder minutes.
We can go "old school" to get durations in hhhh:mi format using a combination of simple builtin functions:
SELECT decode(sign(t.maxst),-1,'-','')||to_char(floor(abs(t.maxst)/60))||
decode(t.maxst,null,'',':')||to_char(mod(abs(t.maxst),60),'FM00')
as MaximumScheduleTime
, decode(sign(t.minst),-1,'-','')||to_char(floor(abs(t.minst)/60))||
decode(t.minst,null,'',':')||to_char(mod(abs(t.minst),60),'FM00')
as MinimumScheduleTime
, decode(sign(t.avgst),-1,'-','')||to_char(floor(abs(t.avgst)/60))
decode(t.avgst,null,'',':')||to_char(mod(abs(t.avgst),60),'FM00')
as AverageScheduleTime
FROM (
SELECT round(max((EndDate - StartDate) *1440),0) as maxst
, round(min((EndDate - StartDate) *1440),0) as minst
, round(avg((EndDate - StartDate) *1440),0) as avgst
FROM table1
) t
Yeah, it's fugly, but it's pretty fast. Here's a simpler case, that shows better what's going on:
select dur as "minutes"
, abs(dur) as "unsigned_minutes"
, floor(abs(dur)/60) as "unsigned_whole_hours"
, to_char(floor(abs(dur)/60)) as "hhhh"
, mod(abs(dur),60) as "unsigned_remainder_minutes"
, to_char(mod(abs(dur),60),'FM00') as "mi"
, decode(sign(dur),-1,'-','') as "leading_sign"
, decode(dur,null,'',':') as "colon_separator"
from (select round(( date_expr1 - date_expr2 )*24*60,0) as dur
from ...
)
(replace date_expr1 and date_expr2 with date expressions)
let's unpack this
date_expr1 - date_expr2 returns difference in number of days
multiply by 1440 (24*60) to get duration in minutes
round (or floor) to resolve fractional minutes into integer minutes
divide by 60, integer quotient is hours, remainder is minutes
abs function to get absolute value (change negative values to positive)
to_char format model FM00 give two digits (leading zeros)
use decode function to format a negative sign and a colon (if needed)
The SQL statement could be made less ugly using a PL/SQL function, one that takes two DATE arguments a duration in (fractional) days and returns formatted hhhh:mi
(untested)
create function hhhhmi(an_dur in number)
return varchar2 deterministic
is
begin
if an_dur is null then
return null;
end if;
return decode(sign(an_dur),-1,'-','')
|| to_char(floor(abs(an_dur)*24))
||':'||to_char(mod((abs(an_dur)*1440),60),'FM00');
end;
With the function defined:
SELECT hhhhmi(max(EndDate - StartDate)) as MaximumScheduleTime
, hhhhmi(min(EndDate - StartDate)) as MinimumScheduleTime
, hhhhmi(avg(EndDate - StartDate)) as AverageScheduleTime
FROM table1

Answer 5

You can use the months_between function to convert dates to the difference in years and then use between the decimal years you are interested:
CASE
WHEN ( ( MONTHS_BETWEEN( TO_DATE(date1, 'YYYYMMDD'),
TO_DATE(date1,'YYYYMMDD'))/12
)
BETWEEN Age1DecimalInYears AND Age2DecimalInYears
)
THEN 'It is between the two dates'
ELSE 'It is not between the two dates'
END;
You may need to change date format to match the a given date format and verify that 31 day months work for your specific scenarios.
References:
( found on www on 05/15/2015 )
1. Oracle/PLSQL: MONTHS_BETWEEN Function
2. Oracle Help Center - MONTHS_BETWEEN