Analyzing data from same tables in diferent db instances.
- by Oscar Reyes
Short version:
How can I map two columns from table A and B if they both have a common identifier which in turn may have two values in column C
Lets say:
A
---
1 , 2
B
---
? , 3
C
-----
45, 2
45, 3
Using table C I know that id 2 and 3 belong to the same item ( 45 ) and thus "?" in table B should be 1.
What query could do something…
