Why I can not join this query with Max date? - mysql

Question

I have an issue with the following mySQL query where it fails when Max date is introduced as shown below.
I get the following error
Error Code: 1054. Unknown column 'order_items.ORDER_ITEM_ID' in 'where
clause'
SET #UserID = 160;
SET #OrderDateTime = '2018-11-13 09:23:45';
SELECT
order_items.ORDER_ID,
listing_region.LIST_REGION_REGION_ID,
listings.LISTING_ID,
order_items.ORDER_REQUIRED_DATE_TIME,
listings.LISTING_NICK_NAME,
order_items.ORDER_QUANTITY,
order_price.ORDER_PRICE_ID,
order_items.ORDER_PORTION_SIZE,
t.LATEST_DATE,
t.ORDER_STATUS
FROM order_status_change, order_items
INNER JOIN listings ON listings.LISTING_ID = order_items.ORDER_LISTING_ID
INNER JOIN listing_region ON listing_region.LIST_REGION_LISTING_ID = listings.LISTING_ID
INNER JOIN order_price ON order_price.ORDERP_ITEM_ID = order_items.ORDER_ITEM_ID
INNER JOIN
(
SELECT MAX(order_status_change.ORDER_STATUS_CHANGE_DATETIME) AS LATEST_DATE, order_status_change.ORDER_ITEM_ID, order_status_change.ORDER_STATUS
FROM order_status_change
WHERE order_status_change.ORDER_ITEM_ID = order_items.ORDER_ITEM_ID
) AS t ON order_status_change.ORDER_ITEM_ID = t.ORDER_ITEM_ID AND order_status_change.ORDER_STATUS_CHANGE_DATETIME = t.LATEST_DATE
WHERE ((order_items.ORDER_USER_ID = #UserID) AND DATE(order_items.ORDER_REQUIRED_DATE_TIME) = DATE(#OrderDateTime))
Any help ?

Answer 1

I have assumed you can join order_status_change on order_items.ID = order_status_change.ORDER_ITEM_ID
If that is valid then I think this will achieve what you are after:
SET #UserID = 160;
SET #OrderDateTime = '2018-11-13 09:23:45';
SELECT
order_items.ORDER_ID
, listing_region.LIST_REGION_REGION_ID
, listings.LISTING_ID
, order_items.ORDER_REQUIRED_DATE_TIME
, listings.LISTING_NICK_NAME
, order_items.ORDER_QUANTITY
, order_price.ORDER_PRICE_ID
, order_items.ORDER_PORTION_SIZE
, t.LATEST_DATE
, order_status_change.ORDER_STATUS
FROM order_items
INNER JOIN listings ON listings.LISTING_ID = order_items.ORDER_LISTING_ID
INNER JOIN listing_region ON listing_region.LIST_REGION_LISTING_ID = listings.LISTING_ID
INNER JOIN order_price ON order_price.ORDERP_ITEM_ID = order_items.ORDER_ITEM_ID
INNER JOIN order_status_change ON order_items.ID = order_status_change.ORDER_ITEM_ID
INNER JOIN (
SELECT
MAX( mc.ORDER_STATUS_CHANGE_DATETIME ) AS LATEST_DATE
, mc.ORDER_ITEM_ID
FROM order_status_change AS mc
GROUP BY
mc.ORDER_ITEM_ID
) AS t
ON order_status_change.ORDER_ITEM_ID = t.ORDER_ITEM_ID
AND order_status_change.ORDER_STATUS_CHANGE_DATETIME = t.LATEST_DATE
WHERE order_items.ORDER_USER_ID = #UserID
AND DATE( order_items.ORDER_REQUIRED_DATE_TIME ) = DATE( #OrderDateTime )
You need to avoid this in future:
FROM order_status_change , order_items
That comma between the 2 table names IS a join, but it is from an older syntax and it is LOWER in precedence than the other joins of your query. Also, by default this comma based join acts as an equivalent to a cross join which MULTIPLIES the number of rows. In brief, please do NOT USE commas between table names.
The other issue is that you were missing a group by clause and I believe you just want to get the "latest" date from this aggregation, once that is determined link back to that table to get the status relevant to that date. (i.e. you can't group by status in the subquery, otherwise you get the latest dateS (one for each status).

Answer 2

Here's a simplified version to illustrate the problem.
DROP TABLE IF exists t,t1;
create table t (id int);
create table t1(id int,dt date);
insert into t values (1),(2);
insert into t1 values (1,'2018-01-01'),(1,'2018-02-01'),(2,'2018-01-01');
select t.*,t2.maxdt
from t
join (select max(dt) maxdt,t1.id from t1 where t1.id = t.id) t2
on t2.id = t.id;
ERROR 1054 (42S22): Unknown column 't.id' in 'where clause'
You could group by in the sub query and then the on clause will come into play
select t.*,t2.maxdt
from t
join (select max(dt) maxdt,t1.id from t1 group by t1.id) t2
on t2.id = t.id;
+------+------------+
| id | maxdt |
+------+------------+
| 1 | 2018-02-01 |
| 2 | 2018-01-01 |
+------+------------+
2 rows in set (0.00 sec)
If you want an answer closer to your problem please add sample data and expected output to the question as text of to sqlfiddle.