Combining Sum/Case queries with different where clauses into one query

Question

Hello,
I'm trying to combine 2 queries that contain the SUM/CASE function into one query that'll produce the output in the same table, rather than having two The thing is, the two queries have different conditions. I've created a sample data table and outputs to better describe what I'm trying to achieve.
SAMPLE_DATA
DEPT
PROD_CODE
FLAG1
FLAG2
HO
A
NULL
Y
HO
B
NULL
Y
HO
A
Y
NULL
HO
B
Y
Y
IT
A
NULL
Y
IT
C
NULL
NULL
ENG
B
NULL
Y
ENG
C
NULL
Y
ENG
C
Y
Y
MKT
A
Y
Y
The first query I'm running is to sum the product codes department wise while checking if FLAG1 is Y. The second query is checking if FLAG2 is Y.
First Query:
select DEPT, sum(case PRODUCT_CODE when 'A' then 1 else 0 end),
sum(case PRODUCT_CODE when 'B' then 1 else 0 end),
sum(case PRODUCT_CODE when 'C' then 1 else 0 end)
from SAMPLE_DATA where FLAG1 is not null group by DEPT;
Second Query:
select DEPT, sum(case PRODUCT_CODE when 'A' then 1 else 0 end),
sum(case PRODUCT_CODE when 'B' then 1 else 0 end),
sum(case PRODUCT_CODE when 'C' then 1 else 0 end)
from SAMPLE_DATA where FLAG2 is not null group by DEPT;
FIRST QUERY OUTPUT:
DEPT
PRODA_FL1
PRODB_FL1
PRODC_FL1
HO
1
1
0
IT
0
0
0
ENG
0
0
1
MKT
1
0
0
SECOND QUERY OUTPUT:
DEPT
PRODA_FL2
PRODB_FL2
PRODC_FL2
HO
1
2
0
IT
1
0
0
ENG
0
1
2
MKT
1
0
0
My aim is to combine both the queries so that the output is displayed the same way as the table below.
DESIRED OUTPUT:
DEPT
PRODA_FL1
PRODB_FL1
PRODC_FL1
PRODA_FL2
PRODB_FL2
PRODC_FL2
Any help or tips will be greatly appreciated. Please note I'm working with more complex data and have simplified my question just to understand how to solve this.

Answer 1

Just treat the two queries as tables, join them on DEPT and produce the results you want.
with q1 as (
select DEPT, sum(case PRODUCT_CODE when 'A' then 1 else 0 end) PRODA_FL1,
sum(case PRODUCT_CODE when 'B' then 1 else 0 end) PRODB_FL1,
sum(case PRODUCT_CODE when 'C' then 1 else 0 end) PRODC_FL1
from SAMPLE_DATA where FLAG1 is not null group by DEPT),
q2 as (
select DEPT, sum(case PRODUCT_CODE when 'A' then 1 else 0 end) PRODA_FL2,
sum(case PRODUCT_CODE when 'B' then 1 else 0 end) PRODB_FL2,
sum(case PRODUCT_CODE when 'C' then 1 else 0 end) PRODC_FL2
from SAMPLE_DATA where FLAG2 is not null group by DEPT;
select q1.dept, proda_fl1, prodb_fl1, prodc_fl1, proda_fl2, prodb_fl2, prodc_fl2
from q1, q2
where q1.dept = q2.dept