Question

I need to delete rows from a table that have 2 columns or more in common. For ex. let’s say that I need to delete rows that have last 2 columns the same.

1 1 2 3

2 2 2 2

3 2 3 3

4 7 3 3

5 4 2 2

First column is the index.

I would need to delete the 4 7 3 3 and 5 4 2 2 (since there are already 2 2 2 2 and 3 2 3 3 in)

Answer 1

After some researching I found this (I think it was somewhere on stack also but can’t remember the post)

  SELECT * FROM tb AS t1
  WHERE EXISTS (
    SELECT 1 FROM tb AS t2 
    WHERE t2.c0= t1.c0
    AND t2.c1= t1.c1
    AND t2.c2= t1.c2
    AND t2.id> t1.id )