Facing a problem and not getting the hint for a few hours. Maybe onyone can help me out.
Have the following query which shows the Topsellers. So the status of the product (active or not) is saved in b.Article_Status (0=inactive, 1=active).
How do I get the products of the result list which have no active product in the productfamily at the moment. But the product shall still be shown if an old one was ordered (and so is in table order_items) is now inactive and the active one was not ordered yet.
Actual query looks as follow. Already fund a solution which works when the actual active product has been ordered once, but still the problem with the mentioned case.
SELECT count( a.order_itemid ) AS numOrders, c.Product_ID, c.Product_Name, d.producer_name
FROM order_items a
LEFT OUTER JOIN product_article b ON b.Article_ID = a.order_itemid
LEFT OUTER JOIN product c ON b.Article_Productid = c.Product_ID
LEFT OUTER JOIN producer d ON c.Product_Producer = d.producer_id
GROUP BY c.Product_ID
ORDER BY `numOrders` DESC
Solution was a WHERE EXISTS subquery
SELECT count( a.order_itemid ) AS numOrders, c.Product_ID, c.Product_Name, d.producer_name
FROM order_items a
LEFT OUTER JOIN product_article b ON b.Article_ID = a.order_itemid
LEFT OUTER JOIN product c ON b.Article_Productid = c.Product_ID
LEFT OUTER JOIN producer d ON c.Product_Producer = d.producer_id
WHERE EXISTS (SELECT * FROM product_article x WHERE c.Product_ID = x.Article_Productid AND x.Article_Status = 1)
GROUP BY c.Product_ID
ORDER BY `numOrders` DESC
LIMIT 5
Related
I have some difficuties to get orders count with the following SQL query:
select
d.id,
d.title,
count(distinct o.id)
from store s
left join `order` o on o.store_id = s.id
left join order_product op on op.order_id=o.id
left join store_product sp on sp.id = op.product_id
left join product p on p.id = sp.product_id
left join department_category_to_entity dce1 on dce1.entity_type IN ('Product') and dce1.entity_id = p.id
left join department_category_to_entity dce2 on op.status != 'replaced' and
op.replacement_id is null and
dce2.entity_type IN ('StoreProduct') and
dce2.entity_id = sp.id
left join department_category_to_entity dce3 on op.status = 'replaced' and
op.replacement_id is not null and
dce3.entity_type IN ('StoreProduct') and
dce3.entity_id = op.replacement_id
left join department_category dc on dc.id = p.department_category_id or
dc.id = dce1.category_id or
dc.id = dce2.category_id or
dc.id = dce3.category_id
left join department d on d.id = dc.department_id
where d.id is not null
group by d.id;
Is it possible to get orders count without sub-queries or to get correct count of orders? Please, help... Thank you!
You have LEFT JOIN, which says to keep looking even if there is no row in the 'right' table. But, on the other hand, you are GROUPing BY a column in the last of a chain of LEFT JOINs! Perhaps you meant JOIN instead of LEFT JOIN??
Saying where d.id is not null is roughly equivalent to saying "Oops, all those LEFT JOINs could have been JOINs.
With GROUP BY and JOINs (LEFT or otherwise), you are doing an "inflate-deflate". What logically happens is all the JOINing is done to build a huge intermediate table with all the valid combinations. Then the COUNT(*) and GROUP BY are done. This tends to make the COUNTs (and SUMs, etc) have bigger values than expected.
What's the most direct route to get from department to order? It does not seem to involve store, so get rid of that table.
Are other tables irrelevant?
Even after addressing those issue, you still may be getting the wrong value. Please provide, for starters, `SHOW CREATE TABLE for each table.
I have four tables products, product_histories, vendor_invoices and invoices
This is the query I have developed
SELECT p.product_id, product_name, vendor_name FROM products AS p
INNER JOIN product_histories AS ph ON p.product_id = ph.product_id
CASE
WHEN ph.history_type = "P" THEN
LEFT JOIN vendor_invoices AS vi ON link_id = vi.vi_id
WHEN ph.history_type = "S" THEN
LEFT JOIN invoices AS i ON i.invoice_id = link_id
END
ORDER BY ph_id ASC
What I want that if ph.history_type is P then is should join vendor_invoices and if it is S then it should join invoices. But it says there is a syntax error.
Can anyone help me out with it? Or could show a better way to achieve this problem.
What I have been trying to achieve is to pull a price based on 3 different variables: brand_id, model_id, motor_id.
The design of the tables that I am working with:
The only issue is that when I add an INNER JOIN for databaseapp_lkp_prices I get a zero result set (fyi, there aren't any prices currently set so databaseapp_lkp_prices is an empty table)
I was expecting to see NULL in place of the price for the 48,000 records that exist when I don't add the databaseapp_lkp_prices INNER JOIN
My query is:
SELECT
a.brand,
b.model,
c.motor,
d.ecu_hardware_ver,
d.ecu_software_ver,
d.ecu_software_upg_ver,
d.ecu_brand,
d.ecu_type,
d.eprom,
d.eprom_desc,
d.`checksum`,
d.checksum16,
c.motor_hp * 1.2 AS motor_hp,
e.price,
c.motor_id,
c.model_id,
c.brand_id
FROM
databaseapp_brand AS a
INNER JOIN databaseapp_model AS b ON b.brand_id = a.brand_id
INNER JOIN databaseapp_motor AS c ON b.model_id = c.model_id
INNER JOIN databaseapp_ecu AS d ON d.motor_id = c.motor_id
INNER JOIN databaseapp_lkp_prices AS e ON c.brand_id = e.brand_id AND c.model_id = e.model_id AND c.motor_id = e.motor_id
ORDER BY
a.brand ASC,
b.model ASC
Anyone able to help me out with why I'm getting a zero result set when I try to look up the price.
Cheers!
Inner join requires match. No match no row. You should try LEFT JOIN instead of INNER JOIN for databaseapp_lkp_prices contribution.
I have three tables, libraryitems, copies and loans.
A libraryitem hasMany copies, and a copy hasMany loans.
I'm trying to get the latest loan entry for a copy only; The query below returns all loans for a given copy.
SELECT
libraryitems.title,
copies.id,
copies.qruuid,
loans.id AS loanid,
loans.status,
loans.byname,
loans.byemail,
loans.createdAt
FROM copies
INNER JOIN libraryitems ON copies.libraryitemid = libraryitems.id AND libraryitems.deletedAt IS NULL
LEFT OUTER JOIN loans ON copies.id = loans.copyid
WHERE copies.libraryitemid = 1
ORDER BY copies.id ASC, loans.createdAt DESC
I know there needs to be a sub select of some description in here, but struggling to get the correct syntax. How do I only return the latest, i.e MAX(loans.createdAt) row for each distinct copy? Just using group by copies.id returns the earliest, rather than latest entry.
Image example below:
in the subquery , getting maximum created time for a loan i.e. latest entry and joining back with loans to get other details.
SELECT
T.title,
T.id,
T.qruuid,
loans.id AS loanid,
loans.status,
loans.byname,
loans.byemail,
loans.createdAt
FROM
(
SELECT C.id, C.qruuid, L.title, MAX(LN.createdAt) as maxCreatedTime
FROM Copies C
INNER JOIN libraryitems L ON C.libraryitemid = L.id
AND L.deletedAt IS NULL
LEFT OUTER JOIN loans LN ON C.id = LN.copyid
GROUP BY C.id, C.qruuid, L.title) T
JOIN loans ON T.id = loans.copyid
AND T.maxCreatedTime = loans.createdAt
A self left join on loans table will give you latest loan of a copy, you may join the query to the other tables to fetch the desired output.
select * from loans A
left outer join loans B
on A.copyid = B.copyid and A.createdAt < B.createdAt
where B.createdAt is null;
This is your query with one simple modification -- table aliases to make it clearer.
SELECT li.title, c.id, c.qruuid,
l.id AS loanid, l.status, l.byname, l.byemail, l.createdAt
FROM copies c INNER JOIN
libraryitems li
ON c.libraryitemid = li.id AND
li.deletedAt IS NULL LEFT JOIN
loans l
ON c.id = l.copyid
WHERE c.libraryitemid = 1
ORDER BY c.id ASC, l.createdAt DESC ;
With this as a beginning let's think about what you need. You want the load with the latest createdAt date for each c.id. You can get this information with a subquery:
select l.copyid, max(createdAt)
from loans
group by l.copyId
Now, you just need to join this information back in:
SELECT li.title, c.id, c.qruuid,
l.id AS loanid, l.status, l.byname, l.byemail, l.createdAt
FROM copies c INNER JOIN
libraryitems li
ON c.libraryitemid = li.id AND
li.deletedAt IS NULL LEFT JOIN
loans l
ON c.id = l.copyid LEFT JOIN
(SELECT l.copyid, max(l.createdAt) as maxca
FROM loans
GROUP BY l.copyid
) lmax
ON l.copyId = lmax.copyId and l.createdAt = lmax.maxca
WHERE c.libraryitemid = 1
ORDER BY c.id ASC, l.createdAt DESC ;
This should give you the most recent record. And, the use of left join should keep all copies, even those that have never been leant.
I have this query (below) while it does work I am wondering if it is the best as it will be going against thousands of records. I will try to explain the best I can.
SELECT items.*,
p.file AS item_pic,
i_f.id AS favorite_id,
COALESCE(f.favorite_count, 0) AS favorite_count,
COALESCE(b.num_buys, 0) AS num_buys,
COALESCE(c.comment_count, 0) AS comment_count
FROM items i
INNER JOIN (SELECT file,
item_id
FROM item_pics
ORDER BY item_pics.id ASC) AS p
ON p.item_id = i.id
LEFT JOIN (SELECT COUNT(*) AS favorite_count,
item_id
FROM item_favorites
GROUP BY item_id) AS f
ON f.item_id = i.id
LEFT JOIN (SELECT COUNT(*) AS num_buys,
item_id
FROM purchases
GROUP BY item_id) AS b
ON b.item_id = i.id
LEFT JOIN (SELECT COUNT(*) AS comment_count,
item_id
FROM comments
GROUP BY item_id) AS c
ON c.item_id = i.id
LEFT JOIN item_favorites AS i_f
ON i.id = i_f.item_id
AND i_f.userid = '14'
GROUP BY i.id
LIMIT 0, 20
So we are selecting the items in the database. The first join is for a picture (Items have multiple pictures but I only want one).
The next join is for favorite count. Each time a user favorites something it adds it to the table favorites with some info, so I am just trying to get the total number of favorites for that item.
Next up is the number of purchases for this item. Pretty much the same as favorites.
After that it is for comments. Again this is just like the purchases and favorites count.
The last join is to see if the logged in user (id 14) has favorited this item if not I use COALESCE to return 0.
Like I said this all works correctly but it does take a few seconds to load on a table of about 6700 items and about 180K rows in the purchases table for only loading 20 at a time (I do a scrolling/load similar to Facebook/Twitter). Indexes have been properly setup on all tables. Once this is complete/correct I would like to know how to limit results for purchases in the last seven days and order by number of purchases (num_buys).
EDIT: Results from EXPLAIN
I suppose you want the first picture (lowest id), and pictures are required, where as everything else is optional.
I guess you're doing subqueries because you think joining on uncorrelated subqueries (hitting the joined tables just once) will be faster than correlated subqueries or a plain JOIN. However, you end up having to lookup the records twice, and the second lookup (for the actual join) doesn't get to use an index because derived (temporary tables) don't have indexes.
Try normal JOINs:
SELECT items.*,
p.file AS item_pic,
COALESCE(i_f.id, 0) AS favorite_id,
COUNT(f.item_id) AS favorite_count,
COUNT(b.item_id) AS num_buys,
COUNT(c.item_id) AS comment_count
FROM items i
STRAIGHT_JOIN item_pics p
ON p.item_id = i.id
LEFT JOIN item_pics p2
ON p2.item_id = i.id
AND p2.id < p1.id
LEFT JOIN item_favorites f
ON f.item_id = i.id
LEFT JOIN purchases b
ON b.item_id = i.id
LEFT JOIN comments c
ON c.item_id = i.id
LEFT JOIN item_favorites AS i_f
ON i_f.item_id = i.id
AND i_f.userid = '14'
WHERE p2.id IS NULL
GROUP BY i.id
LIMIT 20
The double join on pictures is an anti-join WHERE p2.id IS NULL, to retrieve the picture with the lowest id.