Question

I’d like to know how to make paired columns unique key?

I’m working on MySQL workbench, and right now I’ve set two columns (follow,following) to be UQ, I’m assuming this is Unique Key?

So when I tried to insert rows, I tried to insert

follow      following
  3              5
  3              6

But follow is unique key. But i’d like to only do unique key for a pair only, not individual numbers.

Thanks

Answer 1

If i’m not mistaken you have only set a unique key for each column. Maybe you want compound column to be UNIQUE, try

ALTER TABLE tableName ADD CONSTRAINT tb_UQ UNIQUE (follow, following)

if you run the ALTER statement, the example data above is valid but if you try to insert another pair of 3, 5, it is guaranteed to fail.