join on multiple columns
Solution 1:
Agree no matches in your example.
If you mean both columns on either then need a query like this or need to re-examine the data design.
Select TableA.Col1, TableA.Col2, TableB.Val
FROM TableA
INNER JOIN TableB
ON TableA.Col1 = TableB.Col1 OR TableA.Col2 = TableB.Col2
OR TableA.Col2 = TableB.Col1 OR TableA.Col1 = TableB.Col2
Solution 2:
The other queries are all going base on any ONE of the conditions qualifying and it will return a record... if you want to make sure the BOTH columns of table A are matched, you'll have to do something like...
select
tA.Col1,
tA.Col2,
tB.Val
from
TableA tA
join TableB tB
on ( tA.Col1 = tB.Col1 OR tA.Col1 = tB.Col2 )
AND ( tA.Col2 = tB.Col1 OR tA.Col2 = tB.Col2 )
Solution 3:
Below is the structure of SQL that you may write. You can do multiple joins by using "AND" or "OR".
Select TableA.Col1, TableA.Col2, TableB.Val
FROM TableA,
INNER JOIN TableB
ON TableA.Col1 = TableB.Col1 OR TableA.Col2 = TableB.Col2