查询单个表作为主数据和明细，并对结果进行排序，其中主行将位于每个明细的顶部

Question

can this be done? please help me.

I tried union, only it is not sorted like the way i want it - master row on top of detail row. Thank you..

SELECT 
mover.v_id, 
mover.v_registration, 
mover.attached_with       
from ops_vehicle mover
LEFT JOIN v_l_type ON (mover.type = v_l_type.idv_type)
where v_l_type.trailer = FALSE       
union all
SELECT 
trailer.v_id, 
trailer.v_registration, 
trailer.attached_with
from ops_vehicle trailer
LEFT JOIN v_l_type ON (trailer.type = v_l_type.idv_type)
where v_l_type.trailer = TRUE

result: query result

The result i want is something like this:

v_id      v_registration      attached_with
-------------------------------------------
1         ABC 123             4
4         T/B 123
2         CBA 876             5
5         T/B 763
3         OPQ 631

The result row with v_id=4 should be under the v_id=1 because attached_with is 4.

Answer 1

Yes, you can do:

select t.*
from (<your query here>) t
order by coalesce(attached_with, v_id),
         (attached_with is not null) desc,
         v_id