How to set two column unique in SQL.
- by sxingfeng
I am creating a table ,in the table two column is unique, I mean columnA and columnB do not have same value:
such as :
Table X
A B
1 2(RIGHT,unique)
2 2(RIGHT, unique)
1 3(RIGHT, not unique)
2 3(RIGHT, not unique)
1 2 (WRONG, not unique)
How to create such a table?
many thanks!