Question

I’m pretty new to SQL, and am trying to do something not the dumb way. To give some context, I’m comparing the planning and realized uses of vehicles in a carrier branch, and need to count the occurrences of both. I have a with subquery as that returns something like the following

PLANNED  | REALIZED
---------+----------
TRUCK    | BI-TREM
TRUCK    | TRUCK
TRUCK    | TRUCK
TRUCK    | TRUCK
TRUCK    | TRUCK
CARRETA  | CARRETA
CARRETA  | CARRETA
TRUCK    | KOMBI
TRUCK    | BI-TREM
CARRETA  | KOMBI
CARRETA  | KOMBI
TRUCK    | TRUCK
CARRETA  | CARRETA
CARRETA  | BI-TREM
CARRETA  | CARRETA
CARRETA  | CARRETA
TRUCK    | BI-TREM

And would like to return something like the following

VEHICLE | TOTAL_PLANNED | TOTAL_REALIZED
--------+---------------+---------------
CARRETA | 8             | 5
TRUCK   | 9             | 5
BI-TREM | 0             | 4
KOMBI   | 0             | 3

I’ve tried the following

select PLANNED, 
       count(*) as TOTAL_PLANNED
       null as REALIZED,
       0 as TOTAL_REALIZED
from subquery
group by PLANNED

union all

select null as PLANNED,
       0 as TOTAL_PLANNED,
       REALIZED,
       count(*) as TOTAL_REALIZED
from subquery
group by REALIZED

which returns

CARRETA 8   NULL    0
TRUCK   9   NULL    0
NULL    0   BI-TREM 4
NULL    0   CARRETA 5
NULL    0   TRUCK   5
NULL    0   KOMBI   3

I’ve also tried all available joins using the subquery, to no success. In fact, RIGHT JOIN works, but only because all planned vehicles are also in the realized side: if some didn’t, I would have a NULL at the VEHICLE column.

Thanks for any help, even if just a pointer to a SQL command.

PS.: this query have to work on both SQL Server and Oracle, so I’m striving for pure SQL.

Answer 1

Try:

SELECT PLANNED_REALIZED AS VEHICLE, 
       SUM(TOTAL_PLANNED) AS TOTAL_PLANNED,
       SUM(TOTAL_REALIZED) AS TOTAL_REALIZED
FROM
(select PLANNED AS PLANNED_REALIZED, 
        1 as TOTAL_PLANNED
        0 as TOTAL_REALIZED
 from subquery
 union all
 select REALIZED as PLANNED_REALIZED,
        0 as TOTAL_PLANNED,
        1 as TOTAL_REALIZED
 from subquery
) SQ
GROUP BY PLANNED_REALIZED