Mysql select with multiple condition - mysql

Question

I would need help creating a query
Table A
+------------+--------------------+-------+
| product_id | name | price |
+------------+--------------------+-------+
| 13 | Product 13 | 5 |
| 14 | Product 14 | 2 |
| 15 | Product 15 | 3 |
| 16 | Product 16 | 2 |
| 17 | Product 17 | 15 |
+------------+--------------------+-------+
Table B
+----+------------+-------------+
| id | product_id | taxonomy_id |
+----+------------+-------------+
| 10 | 13 | 5 |
| 11 | 13 | 2 |
| 12 | 14 | 3 |
| 13 | 15 | 2 |
| 14 | 16 | 15 |
| 14 | 16 | 5 |
| 14 | 16 | 19 |
| 14 | 16 | 21 |
| 14 | 16 | 18 |
+----+------------+-------------+
my attempt
SELECT *
FROM A
LEFT JOIN B ON B.product_id = A.product_id
WHERE IF(B.taxonomy_id IN ('5','15'),
IF(B.taxonomy_id IN ('2'), 1, 0), 0) = 1
GROUP BY A.product_id
I need it to give me back those results from table A for which it is true
B.taxonomy_id is "5" OR "15" and B.taxonomy_id is "2"
The result would be for this example -> product_id - 13
and I also need to get a number of results SELECT count(*) ... -> return is 1

Answer 1

Is it normal that your tables don't have an id column as a unique primary key ?
Anyway, here is what I came across, tell me if it works :
SELECT table_nameA.product_id
FROM table_nameA
LEFT JOIN table_nameB on table_nameA.product_id = table_nameB.product_id
WHERE taxonomy_id = 2 AND table_nameA.product_id IN
(SELECT table_nameA.product_id
FROM table_nameA
LEFT JOIN table_nameB on table_nameA.product_id = table_nameB.product_id
where taxonomy_id = 5 or taxonomy_id = 15
GROUP BY table_nameA.product_id, taxonomy_id)
Result is :
| product_id |
|------------|
| 13 |
About your count query, it is exactly the same.
SELECT count(table_nameA.product_id) as Quantity
FROM table_nameA
LEFT JOIN table_nameB on table_nameA.product_id = table_nameB.product_id
WHERE taxonomy_id = 2 AND table_nameA.product_id IN
(SELECT table_nameA.product_id
FROM table_nameA
LEFT JOIN table_nameB on table_nameA.product_id = table_nameB.product_id
where taxonomy_id = 5 or taxonomy_id = 15
GROUP BY table_nameA.product_id, taxonomy_id)
Result is :
| Quantity |
|----------|
| 1 |

Answer 2

Instead of doing filtering in the WHERE clause; you need to do this conditional filtering inside the HAVING clause. You can avoid LEFT JOIN, as the product should have taxonomies for them (2 AND (5 or 15)):
SELECT a.product_id
FROM tablea a
JOIN tableb b on b.product_id = a.product_id
GROUP BY a.product_id
HAVING SUM(b.taxonomy_id IN (5,15))
AND SUM(b.taxonomy_id = 2)
Result
| product_id |
| ---------- |
| 13 |
View on DB Fiddle

Answer 3

You can use exists:
select a.*
from a
where exists (select 1
from b
where b.product_id = a.product_id and
b.taxonomy_id in (5, 15)
) and
exists (select 1
from b
where b.product_id = a.product_id and
b.taxonomy_id in (2)
) ;
If you just wanted the product_ids, then I would recommend aggregation:
select b.product_id
from b
where b.taxonomy_id in (2, 5, 15)
group by b.product_id
having sum( b.taxonomy_id in (5, 15) ) > 0 and
sum( b.taxonomy_id in (2) ) > 0 ;

Answer 4

You can use either join with having clause or intersect function with 2 queries to get the output
13
in your senario.
Join with having clause:
select a.product_id from a inner join b on a.product_id = b.product_id group by a.product_id having (SUM (b.taxonomy_id IN (5,15)) and SUM (b.taxonomy_id in (2)));
Intersect with 2 queries:
select a.product_id from a where (a.product_id IN (select product_id from b where b.taxonomy_id = 2))
INTERSECT
select a.product_id from a where (a.product_id IN (select product_id from b where b.taxonomy_id in (5,15)));
For count use something like this which will return
1
as an output:
select COUNT(*) from (select a.product_id from a where (a.product_id IN (select product_id from b where b.taxonomy_id = 2))
INTERSECT
select a.product_id from a where (a.product_id IN (select product_id from b where b.taxonomy_id in (5,15)))) I;