MySQL condition statement across multiple rows - mysql

Question

I have a Profile table like this
|--------|-----------|
| People | Favorite |
|--------|-----------|
| A | Movie |
| B | Movie |
| B | Jogging |
|--------|-----------|
Q: How to retrieve the people whose favorite is movie but not jogging?
In this table, the result is only People A.
Although I came out with this
select People from Profile
where
People
in
(select People from Profile
where favorite='Movie')
and
People
not in
(select People from Profile
where favorite='Jogging')
But it seem like can be better, any suggestion or answer (without using join or union clause)?

Answer 1

https://www.db-fiddle.com/f/rboiDpxxbABCpjtduEz7uY/1
SELECT People
FROM `profile`
GROUP BY people
HAVING SUM('Movie' = favorite) > 0
AND SUM('Jogging' = favorite) = 0

Answer 2

There's lots of ways. While you can use a UNION, its rather messy and innefficient. MySQL doesn't have a MINUS clause which would give a fairly easy to understand query.
You could aggregate the data:
SELECT people
, MAX(IF(favorite='jogging', 1, 0)) as jogging
, MAX(IF(favorite='movie', 1, 0)) as movie
FROM profile
GROUP BY people
HAVING movie=1 AND jogging=0
Or use an outer join:
SELECT m.people
FROM profile m
LEFT JOIN
( SELECT j.people
FROM joggers j
WHERE j.favorite='jogging' ) joggers
ON m.people=joggers.people
WHERE joggers.people IS NULL
AND m.favorite='movies'
Using a NOT IN/NOT EXISTS gives clearer syntax but again would be very innefficient.

Answer 3

There are several query patterns that will return a result that satisfies the specification.
We can use NOT EXISTS with a correlated subquery:
SELECT p.people
FROM profile p
WHERE p.favorite = 'Movie'
AND NOT EXISTS ( SELECT 1
FROM profile q
WHERE q.favorite = 'Jogging'
AND q.people = p.people /* related to row in out query */
)
ORDER
BY p.people
An equivalent result can also be done with an anti-join pattern:
SELECT p.people
FROM profile p
LEFT
JOIN profile q
ON q.people = p.people
AND q.favorite = 'Jogging'
WHERE q.people IS NULL
AND p.favorite = 'Movie'
ORDER BY p.people
Another option is conditional aggregation. Without a guarantee about uniqueness, and some MySQL shorthand:
SELECT p.people
FROM profile p
GROUP
BY p.people
HAVING 1 = MAX(p.favorite='Movie')
AND 0 = MAX(p.favorite='Jogging')
A more portable more ANSI standard compliant syntax for the conditional aggregation:
SELECT p.people
FROM profile p
GROUP
BY p.people
HAVING 1 = MAX(CASE p.favorite WHEN 'Movie' THEN 1 ELSE 0 END)
AND 0 = MAX(CASE p.favorite WHEN Jogging' THEN 1 ELSE 0 END)

Answer 4

This is a common problem when you want to have multiple conditions with the same column. I have answered this here and there are other methods like intersect and subqueries.
SELECT people, GROUP_CONCAT(favorite) as fav
FROM profile
GROUP BY people
HAVING fav REGEXP 'Movie'
AND NOT fav REGEXP 'Jogging';

Answer 5

With group by people and checking the minimum and maximum values of favorite to be 'Movie':
select people from tablename
where favorite in ('Movie', 'Jogging')
group by people
having min(favorite) = 'Movie' and max(favorite) = 'Movie'