Is a combined subquery possible for this scenario? - sql

Question

I currently have this over long query that I'm trying to optimize. I looked at combining subquery's but I fail to get a count for every group in one query while having my constraints.
Is it possible to slim down the following query?
SELECT
val_year,
spg,
SUM(val_q1) val_q1,
SUM(val_q2) val_q2,
SUM(val_q3) val_q3,
SUM(val_q4) val_q4,
SUM(val_q1) + SUM(val_q2) + SUM(val_q3) + SUM(val_q4) val_total
FROM (
SELECT
val_year,
spg,
count_prods val_q1,
0 val_q2,
0 val_q3,
0 val_q4
FROM table_report
WHERE val_quarter = 'Q1'
UNION ALL
SELECT
val_year,
spg,
0 val_q1,
count_prods val_q2,
0 val_q3,
0 val_q4
FROM table_report
WHERE val_quarter = 'Q2'
UNION ALL
SELECT
val_year,
spg,
0 val_q1,
0 val_q2,
count_prods val_q3,
0 val_q4
FROM table_report
WHERE val_quarter = 'Q3'
UNION ALL
SELECT
val_year,
spg,
0 val_q1,
0 val_q2,
0 val_q3,
count_prods val_q4
FROM table_report
WHERE val_quarter = 'Q4'
)
table_report looks like this:
table_report:
val_year VARCHAR2(4)
spg VARCHAR2(256)
val_quarter VARCHAR2(2)
count_prods NUMBER(10)

Answer 1

You can replace the UNIONs with a single query using CASEs:
SELECT
val_year,
spg,
CASE WHEN val_quarter = 'Q1' THEN count_prods ELSE 0 END val_q1,
CASE WHEN val_quarter = 'Q2' THEN count_prods ELSE 0 END val_q2,
CASE WHEN val_quarter = 'Q3' THEN count_prods ELSE 0 END val_q3,
CASE WHEN val_quarter = 'Q4' THEN count_prods ELSE 0 END val_q4
FROM table_report

Answer 2

It looks like a PIVOT query, so you could do all in one
SELECT
val_year, spg,
coalesce(q1_total, 0) as q1,
coalesce(q2_total, 0) as q2,
coalesce(q3_total, 0) as q3,
coalesce(q4_total, 0) as q4,
coalesce(q1_total, 0) + coalesce(q2_total, 0) + coalesce(q3_total, 0) + coalesce(q4_total, 0) as total
FROM
(SELECT val_Year, spg, count_prod, val_quarter FROM test)
PIVOT (SUM(count_prod) as total
FOR (val_Quarter) IN ('Q1' AS q1, 'Q2' AS q2, 'Q3' AS q3, 'Q4' as q4))s ;
see SqlFiddle

Answer 3

As per my understanding, you can directly use group by query to get the sum count of each quarter -
like
select sum(count_prods) mysum, val_quarter as quarter group by quarter;

Answer 4

I'm not sure exactly what result you are trying to obtain, but perhaps you can try an approach like this:
SELECT
val_year,
spg,
val_q1,
val_q2,
val_q3,
val_q4,
val_q1 + val_q2 + val_q3 + val_q4 as val_total
FROM (
SELECT
val_year,
spg,
sum(case when val_quarter = 'Q1' then count_prods else 0 end) as val_q1,
sum(case when val_quarter = 'Q2' then count_prods else 0 end) as val_q2,
sum(case when val_quarter = 'Q3' then count_prods else 0 end) as val_q3,
sum(case when val_quarter = 'Q4' then count_prods else 0 end) as val_q4
FROM table_report
GROUP BY val_year, spg
)
Here it is in a no-data fiddle : http://sqlfiddle.com/#!4/9bf262/20