mysql - SQL Compare rows -

okay here situation: following data in table.

pair_no no          no2  3       5678efgh    1234abcd 4       1111bbbb    0000aaaa 1       1234abcd    5678efgh 2       0000aaaa    1111bbbb

the constraints if no = no2 in row skip row. in sample data rows selected should pair no 3 , 4.

i have tried merge , inner join self keep getting 4 rows back.

i have tried insert table not exists again 4 rows inserted.

   select a.* pairs    inner join pairs b on a.no=b.no2 , a.no2=b.no;

i thinking maybe selecting distinct number column 1 , check in column 2 think yield same 4 rows.

i may on thinking problem , maybe here can @ , see solution hiding.

i testing on mysql should run on sqlserver 2008. have searched questions didn't seem match data set issue.

taking @ word, meaning selecting records value of no column not appear anywhere in no2 column in same table, try this:

select a.pair_no, a.no, a.no2 pairs  left join pairs b on(a.no = b.no2) b.pair_no null -- assuming column not nullable

another option use not exists:

select pair_no, no, no2 pairs not exists(     select 1     pairs b     b.no2 = a.no )

i prefer left join option since it's shorter , more readable.
both of these statement should work on both mysql , sql server.

UV code