[SOLVED] how do I delete duplicates in two colums?

[n8w]

I thought this would be easy but it doesn't work

I want to delete all records that have the same ids in two colums

 

for example I tried

DELETE FROM mytable WHERE userid=judgeid 

 

So I would like to delete row 2 in the example below

 

row #useridjudgeid

1 1231 2213

2 1122 1122

3 3234 123

4 543 443

[fenway]

You'd need to delete using a self join.

[n8w]

thanks!

 

I looked up self joins and it still isn't clear how to do it .. as far as syntax .. can you show me an example?

 

Thanks

[fenway]

DELETE t1 FROM mytable AS t1 INNER JOIN mytable AS t2 ON t1.userid=t2.judgeid

[n8w]

very interesting .. thanks so much for your help!