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## Re: [HACKERS] No: implied sort with group by

### In response to

### pgsql-hackers by date

> > Not necessarily true; as I said, I get the same result as above (with the 980112 > > source tree; have things changed since??). Perhaps you are running into the sorting > > problem which seemed to be present on larger tables only? > > > > postgres=> select b,c,sum(a) from t1 group by b,c; > > b|c|sum > > -+-+--- > > |x| 5 > > |z| 3 > > (2 rows) > > > > postgres=> select * from t1; > > a|b|c > > -+-+- > > 1| |x > > 2| |x > > 2| |x > > 3| |z > > (4 rows) > > Hmmm...I have a snapshot from about ten days ago > Is the order from the second query the order that the rows were inserted? > > Do you get the same results if you insert the (3,null,'z') second or third so > the rows are stored out of order? I was getting my bad results with this same > data, only four rows. OUCH! You are right, there is a problem with this simple test case: postgres=> select b,c,sum(a) from t1 group by b,c; b|c|sum -+-+--- |x| 5 |z| 3 |x| 0 (3 rows) postgres=> select * from t1; a|b|c -+-+- 1| |x 2| |x 2| |x 3| |z 0| |x (5 rows) I just inserted a single out-of-order row at the end of the table which, since the integer value is zero, should have not affected the result. Sorry I didn't understand the nature of the test case. - Tom

- Re: [HACKERS] No: implied sort with group by at 1998-01-28 14:02:34 from Darren King

Next: From:Bruce MomjianDate:1998-01-28 16:34:23Subject: Re: [HACKERS] functions with same name, different argsPrevious: From: Darren KingDate: 1998-01-28 14:02:34Subject: Re: [HACKERS] No: implied sort with group by