row deletion in mysql

Question

I have a table say incompatible which has two columns namely codeA and codeB. Now, I have two entries as A, B and B, A if A is incompatible to B. My question is how do I remove one of the rows from the table in mysql?

Answer 1

Try this:

DELETE t1 FROM incompatible AS t1
INNER JOIN incompatible AS t2 ON t1.codeA = t2.codeB AND t2.codeB = t1.codeA 
WHERE t1.codeA > t1.codeB

Demo here