How to check for unique value depending on another column value...

[Abhilash Etikala]

I am having table which contains 2 columns (qid,round) and both columns can have repeated values but one constraint is for each 'round' the 'qid' values should not be repeated.

example:
round:1,1,1,2,2
qid:1,2,3,1,2---should be unique for each round...

can any body suggest me a query for this..??

[rski]

So you need unique constraint on both columns (qid,round)

[Abhilash Etikala]

ya..depending on each other...

[rski]

What do you mean? My english is not as good i'm afraid :).

[Abhilash Etikala]

i mean the same as u said unique constraint on both columns...i think you understood what was my problem....

[rski]

Yes I understood (i think i did) and that's why i suggested to create one uniqe constraint on both column because you want the pair of values (round,qid) to be unique don't you?

[Abhilash Etikala]

ya exactly....so how to get it...and wat cud be the query...

[Abhilash Etikala]

Hi rski, i got solution of course it was easy...just set a unique constraint on two columns by UNIQUE(column1, column2)...I think it is basic concept but i am very new to postgre sql....Thank you....