In the below query ,if there is no row with ORIG_TERM_IND as 'T' the whole query fails ,even though there are rows with value as 'O'.

What I want is that CALLING should display the sum of those rows which have ORIG_TERM_IND as 'O' and CALLED should display 0

SELECT SUM(E1.DUR) CALLING,
SUM(E2.DUR) CALLED
FROM
Table a E1,
Table a E2
WHERE
E2.LOGIN=E1.LOGIN
AND E1.ORIG_TERM_IND = 'O'
AND E2.ORIG_TERM_IND ='T'
GROUP BY
E1.LOGIN

Thanks in advance

I am not sure whether I understand your porblem but try this code...it may help you...

SELECT SUM(E1.DUR) CALLING,
SUM(E2.DUR) CALLED
FROM
Table a E1,
Table a E2
WHERE
E2.LOGIN=E1.LOGIN
AND
(E1.ORIG_TERM_IND = 'O' OR E2.ORIG_TERM_IND ='T')
GROUP BY
E1.LOGIN

Sorry ,but that wont help becuase by putting OR both CALLING and CALLED would display the same values .
I want CALLING to display sum of those rows whihc have value as 'O' and CALLED to display sum of those rows which have value as 'T'.

I'm new of here, so I take this to present myself: I'm from Italy and I worked mainly on oracle,mssql and mysql

a better solution that query the table once can be this (I assume you use oracle,but it can be translate easily)

select
sum(decode(ORIG_TERM_IND,'O',DUR,0)) CALLING,
sum(decode(ORIG_TERM_IND,'T',DUR,0)) CALLED
from table
group by login

zeus77's approach written in standard sql --
another approach:
yet another approach:

I didn't know 'case when then else' is in standard SQL.... good to know, thanks