Return result of several set operations on subqueries - mysql

Question

I am using MySql and running the following queries.
(select CONCAT(RESOURCE, " AMB:", AMB) AS REC_1 from db.CRE
where CONTENT = '183' and LEVEL = '99'
EXCEPT
select CONCAT(RESOURCE, " AMB:", AMB) AS REC_1 from db.CRE
where CONTENT = '182' and LEVEL = '99')
(select CONCAT(RESOURCE, " AMB:", AMB) AS REC_SAME from db.CRE
where CONTENT = '183' and LEVEL = '99'
INTERSECT
select CONCAT(RESOURCE, " AMB:", AMB) AS REC_SAME from db.CRE
where CONTENT = '182' and LEVEL = '99')
(select CONCAT(RESOURCE, " AMB:", AMB) AS REC_2 from db.CRE
where CONTENT = '182' and LEVEL = '99'
EXCEPT
select CONCAT(RESOURCE, " AMB:", AMB) AS REC_2 from db.CRE
where CONTENT = '183' and LEVEL = '99')
The subqueries are always the same but the set operation changes. All of these queries work on their own. The first tells me the feature unique to subquery a the second what both share and the third what is unique to subquery b. The issue is that I would like to get all three of these returned at the same time. One column being REC_1 another REC_SAME another REC_2.
I have tried using UNIONS to join the but this fails if any of them are null. I have also tried using select without a from but it also didn't work.
The results i would expect to be with the following structure.In which rec1 would contain the results of the first query , rec_same of the intersect query and rec_2 of the last query.
Rec1|Rec_same|Rec2

Answer 1

AS MySQL doesn't support FULL OUTER JOIN you have to build it by hand
SELECT
REC_1,REC_SAME,REC_2
FROM
(SELECT
REC_1,REC_SAME
FROM
((select CONCAT(RESOURCE, " AMB:", AMB) AS REC_1 from CRE
where CONTENT = '183' and `LEVEL` = '99'
EXCEPT
select CONCAT(RESOURCE, " AMB:", AMB) AS REC_1 from CRE
where CONTENT = '182' and `LEVEL` = '99')) a1
LEFT JOIN
((select CONCAT(RESOURCE, " AMB:", AMB) AS REC_SAME from CRE
where CONTENT = '183' and `LEVEL` = '99'
INTERSECT
select CONCAT(RESOURCE, " AMB:", AMB) AS REC_SAME from CRE
where CONTENT = '182' and `LEVEL` = '99')) a2 ON a1.REC_1 = a2.REC_SAME
UNION
SELECT
REC_1,REC_SAME
FROM
(((select CONCAT(RESOURCE, " AMB:", AMB) AS REC_1 from CRE
where CONTENT = '183' and `LEVEL` = '99'
EXCEPT
select CONCAT(RESOURCE, " AMB:", AMB) AS REC_1 from CRE
where CONTENT = '182' and `LEVEL` = '99')) a1
RIGHT JOIN
((select CONCAT(RESOURCE, " AMB:", AMB) AS REC_SAME from CRE
where CONTENT = '183' and `LEVEL` = '99'
INTERSECT
select CONCAT(RESOURCE, " AMB:", AMB) AS REC_SAME from CRE
where CONTENT = '182' and `LEVEL` = '99')) a2 ON a1.REC_1 = a2.REC_SAME) ) b1
LEFT JOIN
(select CONCAT(RESOURCE, " AMB:", AMB) AS REC_2 from CRE
where CONTENT = '182' and LEVEL = '99'
EXCEPT
select CONCAT(RESOURCE, " AMB:", AMB) AS REC_2 from CRE
where CONTENT = '183' and LEVEL = '99') b2 ON b1.REC_1 = b2.REC_2 OR b1.REC_SAME = b2.REC_2
UNION
SELECT
REC_1,REC_SAME,REC_2
FROM
(SELECT
REC_1,REC_SAME
FROM
((select CONCAT(RESOURCE, " AMB:", AMB) AS REC_1 from CRE
where CONTENT = '183' and `LEVEL` = '99'
EXCEPT
select CONCAT(RESOURCE, " AMB:", AMB) AS REC_1 from CRE
where CONTENT = '182' and `LEVEL` = '99')) a1
LEFT JOIN
((select CONCAT(RESOURCE, " AMB:", AMB) AS REC_SAME from CRE
where CONTENT = '183' and `LEVEL` = '99'
INTERSECT
select CONCAT(RESOURCE, " AMB:", AMB) AS REC_SAME from CRE
where CONTENT = '182' and `LEVEL` = '99')) a2 ON a1.REC_1 = a2.REC_SAME
UNION
SELECT
REC_1,REC_SAME
FROM
(((select CONCAT(RESOURCE, " AMB:", AMB) AS REC_1 from CRE
where CONTENT = '183' and `LEVEL` = '99'
EXCEPT
select CONCAT(RESOURCE, " AMB:", AMB) AS REC_1 from CRE
where CONTENT = '182' and `LEVEL` = '99')) a1
RIGHT JOIN
((select CONCAT(RESOURCE, " AMB:", AMB) AS REC_SAME from CRE
where CONTENT = '183' and `LEVEL` = '99'
INTERSECT
select CONCAT(RESOURCE, " AMB:", AMB) AS REC_SAME from CRE
where CONTENT = '182' and `LEVEL` = '99')) a2 ON a1.REC_1 = a2.REC_SAME) ) b1
RIGHT JOIN
(select CONCAT(RESOURCE, " AMB:", AMB) AS REC_2 from CRE
where CONTENT = '182' and LEVEL = '99'
EXCEPT
select CONCAT(RESOURCE, " AMB:", AMB) AS REC_2 from CRE
where CONTENT = '183' and LEVEL = '99') b2 ON b1.REC_1 = b2.REC_2 OR b1.REC_SAME = b2.REC_2

Answer 2

You can add rec_type('rec_1', 'rec_same','rec_2') columns in all 3 subqueries, and then perform a union. At the end, use group by and sum function to exact which rec is rec_1/rec_same/rec_2. See the example query:
WITH rec_1 as(
(select CONCAT(RESOURCE, " AMB:", AMB) AS REC, 'rec_1' as rec_type from db.CRE
where CONTENT = '183' and LEVEL = '99'
EXCEPT
select CONCAT(RESOURCE, " AMB:", AMB) AS REC, 'rec_1' as rec_type from db.CRE
where CONTENT = '182' and LEVEL = '99')
),
rec_same AS (
(select CONCAT(RESOURCE, " AMB:", AMB) AS REC, 'rec_same' as rec_type from db.CRE
where CONTENT = '183' and LEVEL = '99'
INTERSECT
select CONCAT(RESOURCE, " AMB:", AMB) AS REC,'rec_same' as rec_type from db.CRE
where CONTENT = '182' and LEVEL = '99')
),
rec_2 AS (
(select CONCAT(RESOURCE, " AMB:", AMB) AS REC,'rec_2' as rec_type from db.CRE
where CONTENT = '182' and LEVEL = '99'
EXCEPT
select CONCAT(RESOURCE, " AMB:", AMB) AS REC, 'rec_2' as rec_type from db.CRE
where CONTENT = '183' and LEVEL = '99')
),
rec_union AS(
select
REC, rec_type
FROM
rec_1
UNION
select
REC, rec_type
FROM
rec_same
UNION
select
REC, rec_type
FROM
rec_2
)
select
rec,
sum(rec_type = 'rec_1') as is_rec_1,
sum(rec_type = 'rec_same') as is_rec_same,
sum(rec_type = 'rec_2') as is_rec_2
from
rec_union
group by rec

Answer 3

You can do:
with
a as (select concat(resource, " AMB:", amb) as c from cre where content = '183' and level = '99'),
b as (select concat(resource, " AMB:", amb) as c from cre where content = '182' and level = '99')
select *
from (
select 'same' as type, a.c from a join b on b.c = a.c
union all select 'rec1' as type, a.c from a left join b on b.c = a.c where b.c is null
union all select 'rec2' as type, b.c from b left join a on b.c = a.c where a.c is null
) x;
Result:
type c
----- -------
same 3 AMB:4
rec1 5 AMB:6
rec2 1 AMB:2
See running example at db<>fiddle.