Conditional Order By

Question

I have a table where there is a set of routes with a start label and end label. each row has a column "progres" which is the column where to apply the global "order by" clause, and finally a selection column that tells which label types must be ordered (Odd, Even or All). if LabelStart > LabelEnd => order by ASC else by DESC for example here are the routes path ``` Routes ID RouteID, Progres, LabelStart, LabelEnd Type 1 1 5 1 21 O 2 1 10 10 2 E 4 2 15 2 25 A 5 3 20 1 11 O 6 3 22 4 10 E 7 4 30 5 11 O 8 4 31 2 12 E ``` and here the points belonging to routes ``` Points PoinID RouteID, Label 1 1 3 2 1 2 4 1 1 5 1 8 6 1 5 7 1 6 8 1 9 9 1 21 10 1 10 11 1 11 12 2 1 13 2 2 14 2 12 15 2 3 16 2 25 17 2 14 ... ``` What I need is a table where all the points are ordered globally by Routes Proges, grouped by Even, Odd or All based on types and finally ordered by ASC if LabelStart > LabelEnd else by DESC. the result shoud be: ``` ID RouteID, PointID 1 1 4 2 1 1 4 1 6 5 1 8 6 1 11 7 1 9 8 1 10 9 1…

Accepted Answer

SQL Fiddle

```
select 
    row_number() over() id, *
from (
    select
        r.routeid,
        p.pointid,
        label,
        type,
        labelstart,
        labelend
    from
        route r
        inner join
        point p on p.routeid = r.routeid
    where
        r.type = 'E' and p.label % 2 = 0
        or
        r.type = 'O' and p.label % 2 != 0
        or
        r.type = 'A'
    order by
        r.routeid, r.progres, r.id,
        case labelstart < labelend
            when true then label
            else label * - 1
        end
) s
```

Conditional Order By

Solution

Problem