I'm trying to figure out without disabling "only_full_group_by" in my.ini
here is my query:
SELECT
p.title,
COUNT(t.qty) AS total
FROM
payments t
LEFT JOIN products AS p
ON p.id = t.item
WHERE t.user = 1
GROUP BY t.item
ORDER BY t.created DESC;
and tables:
Payments:
id item user created
============================
1 1 1 2017-01-10
2 2 1 2017-01-11
3 3 1 2017-01-12
4 4 1 2017-01-13
5 1 1 2017-01-14
Products:
id title created
==========================
1 First 2016-12-10
1 Second 2016-12-11
1 Third 2016-12-12
1 Fourth 2016-12-13
The final result should look lie:
Name Total
First 2
Second 1
Third 1
Fourth 1
But if I change my query to GROUP BY t.item, t.created Error is gone, but I end up with five records instead of four, which is not what I want. Since I'm grouping items based on "item" field, there should be only four records
This is your query:
SELECT p.title, COUNT(t.qty) AS total
-------^
FROM payments t LEFT JOIN
products AS p
ON p.id = t.item
WHERE t.user = 1
GROUP BY t.item
---------^
ORDER BY t.created DESC;
---------^
The pointed to places have issues. Notice that the SELECT and GROUP BY are referring to different column. In a LEFT JOIN, you (pretty much) always want to aggregate by something in the first table, not the second.
The ORDER BY is another problem. You are not aggregating by this column, so you need to decide which value you want. I am guessing MIN() or MAX():
SELECT p.title, COUNT(t.qty) AS total
FROM payments t LEFT JOIN
products AS p
ON p.id = t.item
WHERE t.user = 1
GROUP BY p.title
ORDER BY MAX(t.created) DESC;
I will also add that COUNT(t.qty) is suspect. Normally qty refers to "quantity" and what you want is the sum: SUM(t.qty).