I'm trying to select only the highest kw (model table) for each category (type table).
Model table
+-----+----+---------+
| id | kw | type_id |
+-----+----+---------+
| 1 | 2 | 1 |
| 2 | 5 | 1 |
| 3 | 10 | 2 |
| 4 | 4 | 2 |
| 5 | 5 | 2 |
| 6 | 4 | 3 |
| 7 | 3 | 4 |
| 8 | 7 | 5 |
+-----+----+---------+
Type table
+-----+----------+
| id | category |
+-----+----------+
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 2 |
| 5 | 2 |
+-----+----------+
Attempts
1. this query returns a list of all the kws and categories:
SELECT A.kw, B.category
FROM AC_MODEL A
INNER JOIN AC_TYPE B ON A.type_id = B.id
ORDER BY A.kw DESC
2. I tried to do something like this answer but it doesn't work:
SELECT A.kw, B.category
FROM AC_MODEL A
INNER JOIN AC_TYPE B ON A.type_id = B.id
ORDER BY A.kw DESC
WHERE (A.kw, B.category) IN (
SELECT MAX(A.kw), B.category
FROM AC_MODEL A
INNER JOIN AC_TYPE B ON A.type_id = B.id
GROUP BY B.category
)
Does anybody have an idea?
Use MAX and GROUP BY
SELECT MAX(m.kw), t.category
FROM model m
INNER JOIN type t ON m.type_id = t.id
GROUP BY t.category
OUTPUT
MAX(m.kw) category
10 1
7 2
SQL FIDDLE: http://sqlfiddle.com/#!9/5d0df/5/0
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