MySQL join table to itself based on row number returns no data

Question

I\'ve got a logs table with an ID column in it, and I want to do the following:

• Select the ID and row number
• Join the table to itself based on the row num

Answer 1

Change your variable name in second query, using same variable in both queries can produce unexpected results

select * from 
    (select id, @rownum := @rownum + 1 as 'row' 
        from logs, (select @rownum := 0) r order by id) a
join
    (select id, @rownum1 := @rownum1 + 1 as 'row1' 
        from logs, (select @rownum1 := 0) r order by id) b
on a.row = b.row1;