All we need is an easy explanation of the problem, so here it is.
Actually might be a simple question:
Given 2 tables:
table1: A,B,C (A1,B1,28471), (A1,B2,01244), (A2,B1,1283a), (A2,B2,82r7e); table2: A,B,D,E,F,G (A1,B1,18,1,6,8), (A2,B2,18,2,3,0), (A3,B1,18,7,1,4), (A4,B2,18,1,9,6);
Will the following statement result in a the following result given the example tables:
SELECT E,F,G FROM table2 WHERE (A,B) IN (SELECT A,B FROM table1)
E F G (1,6,8), -- (A1,B1) (2,3,0); -- (A2,B2)
Can someone confirm this is a valid method to select based on tuples?
asking as the most likely next step is to UPDATE the E field by adding +5 for matching results
How to solve :
I know you bored from this bug, So we are here to help you! Take a deep breath and look at the explanation of your problem. We have many solutions to this problem, But we recommend you to use the first method because it is tested & true method that will 100% work for you.
SELECT E,F,G FROM table2 t2 WHERE EXISTS ( SELECT FROM table1 t1 WHERE (t1.A,t1.B) = (t2.A,t2.B) );
Equivalent and typically cheaper.
And the negation
NOT EXISTS is not as treacherous as the discouraged (not completely equivalent)
NOT IN. See:
Aside, I would call
(A,B) a "composite type" or "row type" rather than a "tuple".
Thanks to Peter Vandivier (couldnt flag his comment as the answer)
Yes it is possible:
What have you tried😉 – Peter Vandivier 12 mins ago
Note: Use and implement method 1 because this method fully tested our system.
Thank you 🙂