canalmidi: select pk, number, name, type, count, depth, 'Distance to ' || lag(name) over ( order by number asc ) || ': ' || round( ( pk - nullif( lag(pk) over ( order by number asc ), 0.0 ) ), 2 ) as distance_previous, 'Distance to ' || lead(name) over ( order by number asc ) || ': ' || round( ( nullif( lead(pk) over ( order by number asc ), 0.0 ) - pk ), 2 ) as distance_next from locks where pk between :minpk and :maxpk