समय अंतराल करना, और विशेष रूप से कई अंतरालों या अंतराल समूहों में एकत्रीकरण (राशि, औसत) करना Oracle में सीधा नहीं है। AVG फ़ंक्शन टाइमस्टैम्प अंतराल पर काम नहीं करता है, यह संख्याओं की अपेक्षा करता है। इसलिए, हमें अपना खुद का एग्रीगेशन ऑब्जेक्ट और फंक्शन बनाना होगा जो ऐसा करेगा।
सबसे पहले, ऑब्जेक्ट विनिर्देश :
CREATE OR REPLACE TYPE AvgInterval
AS OBJECT (
runningSum INTERVAL DAY(9) TO SECOND(9),
runningCnt number,
STATIC FUNCTION ODCIAggregateInitialize
( actx IN OUT AvgInterval
) RETURN NUMBER,
MEMBER FUNCTION ODCIAggregateIterate
( self IN OUT AvgInterval,
val IN DSINTERVAL_UNCONSTRAINED
) RETURN NUMBER,
MEMBER FUNCTION ODCIAggregateTerminate
( self IN AvgInterval,
returnValue OUT DSINTERVAL_UNCONSTRAINED,
flags IN NUMBER
) RETURN NUMBER,
MEMBER FUNCTION ODCIAggregateMerge
(self IN OUT AvgInterval,
ctx2 IN AvgInterval
) RETURN NUMBER
);
और ऑब्जेक्ट बॉडी :
CREATE OR REPLACE TYPE BODY AvgInterval AS
STATIC FUNCTION ODCIAggregateInitialize
( actx IN OUT AvgInterval
) RETURN NUMBER IS
BEGIN
IF actx IS NULL THEN
actx := AvgInterval (INTERVAL '0 0:0:0.0' DAY TO SECOND, 0);
ELSE
actx.runningSum := INTERVAL '0 0:0:0.0' DAY TO SECOND;
actx.runningCnt := 0;
END IF;
RETURN ODCIConst.Success;
END;
MEMBER FUNCTION ODCIAggregateIterate
( self IN OUT AvgInterval,
val IN DSINTERVAL_UNCONSTRAINED
) RETURN NUMBER IS
BEGIN
self.runningSum := self.runningSum + val;
self.runningCnt := self.runningCnt + 1;
RETURN ODCIConst.Success;
END;
MEMBER FUNCTION ODCIAggregateTerminate
( self IN AvgInterval,
ReturnValue OUT DSINTERVAL_UNCONSTRAINED,
flags IN NUMBER
) RETURN NUMBER IS
BEGIN
if (runningCnt <> 0) then
returnValue := (self.runningSum/runningCnt);
else
returnValue := self.runningSum;
end if;
RETURN ODCIConst.Success;
END;
MEMBER FUNCTION ODCIAggregateMerge
(self IN OUT AvgInterval,
ctx2 IN AvgInterval
) RETURN NUMBER IS
BEGIN
self.runningSum := self.runningSum + ctx2.runningSum;
self.runningCnt := self.runningCnt + ctx2.runningCnt;
RETURN ODCIConst.Success;
END;
END;
आखिरकार, फ़ंक्शन जो उपरोक्त वस्तु का उपयोग करता है :
CREATE OR REPLACE FUNCTION avg_interval( x DSINTERVAL_UNCONSTRAINED)
RETURN DSINTERVAL_UNCONSTRAINED PARALLEL_ENABLE
AGGREGATE USING AvgInterval;
अब, हम इसका उपयोग कर सकते हैं इस तरह :
with x as (
select systimestamp - 1/24 as created_date, systimestamp as modified_date from dual
union
select systimestamp - 2/24 as created_date, systimestamp as modified_date from dual
union
select systimestamp - 3/24 as created_date, systimestamp as modified_date from dual
)
select avg_interval(modified_date - created_date)
from x;
आउटपुट:
+00 02:00:00.562669
हम समूहों पर को भी एकत्रित कर सकते हैं इसके साथ :
with x as (
select 'FL' as state, to_dsinterval('0 00:56:30') as duration from dual
union
select 'FL' as state, to_dsinterval('0 02:08:40') as duration from dual
union
select 'GA' as state, to_dsinterval('0 01:01:00') as duration from dual
)
select state, avg_interval(duration)
from x
group by state;
आउटपुट:
FL +00 01:32:35.000000
GA +00 01:01:00.000000