I'm trying to speed up the following query as it takes quite long to run: now it's 'only' about 1.5 seconds, but it will certainly get slower with more rows (which will 10x over the next period).
Basically, I want to show all the rows from the orders table for the user, and per row show the total order amount (which is the SUM of the orders_products table).
SELECT
orders.order_number,
orders.order_date,
companies.company_name,
COALESCE(SUM(orders_products.product_price * orders_products.product_quantity),0) AS order_value
FROM orders
LEFT JOIN companies ON companies.id = orders.company_id
LEFT JOIN orders_products ON orders_products.order_id = orders.id
LEFT JOIN users ON users.id = orders.user_id
WHERE orders.user_id = '$user_id'
AND companies.user_id = '$user_id'
GROUP BY orders.id ORDER BY orders.order_date DESC, orders.order_number DESC
I've tried adding another condition AND orders_products.user_id = '$user_id'. Speed wise the query was about 12x faster (yeah!) but the problem is that not all orders have products in them. In this case, the orders without products in them are not returned.
How do I change my query so that despite of an order not having products in them, it still is returned (with total order value 0), whilst also speeding up the query?
Thank you in advance for your help!
You might find it faster to use a correlated subquery:
SELECT o.order_number, o.order_date, c.company_name,
(SELECT COALESCE(SUM(op.product_price * op.product_quantity), 0)
FROM orders_products op
WHERE op.order_id = o.id
) AS order_value
FROM orders o LEFT JOIN
companies c
ON c.id = o.company_id AND c.user_id = o.user_id
WHERE o.user_id = '$user_id'
ORDER BY o.order_date DESC, o.order_number DESC
This gets rid of the outer aggregation which is often a performance win.
Then for performance you want the following indexes:
orders(user_id, order_date desc, order_number_desc, company_id)
companies(id, company_id, company_name)
orders_products(order_id, product_price, product_quantity)
Related
I have a Products table and an Orders table defined in such a way that I can do JOIN query as the following to return Products with zero orders for a specific user.
This query works but its very slow.
select * from products where id not in (select product_id from orders where user_id = 1)
The question is, how to write same query better way and faster?
No need of a subquery for that:
SELECT p.product_id
FROM
Products p
LEFT JOIN Order o ON p.product_id = o.product_id AND o.user_id = #UserId
WHERE
o.order_id IS NULL -- or any other field that cannot be null on Order
EDIT: for increased performance you may want to check as well that you have indexes in place on the Order user_id column and on your ids (more likely you have them there and probably clustered indexes, both worth to check)
You should be able to do simple LEFT JOIN
SELET * FROM products
LEFT JOIN orders ON (orders.product_id=products.id and orders.user_id=1)
WHERE orders.id IS NULL;
SELECT P.*
FROM products P
LEFT JOIN (SELECT product_id from orders where user_id = 1) O
ON P.id = O.product_id
WHERE O.product_id IS NULL
I have a projects table and a tasks table I want to do a query that gets all projects and the sum of the time_spent columns grouped by project id. So essentially list all projects and get the total of all the time_spent columns in the tasks table belonging to that project.
With the query posted below I get the latest added time_spent column and not the sum of all the columns.. :S
Below is the query I have at the moment:
SELECT `projects`.`id`, `projects`.`description`, `projects`.`created`,
`users`.`title`, `users`.`firstname`, `users`.`lastname`, `users2`.`title`
as assignee_title, `users2`.`firstname` as assignee_firstname,
`users2`.`lastname` as assignee_lastname,
(select sum(tasks2.time_spent)
from tasks tasks2
where tasks2.id = tasks.id)
as project_duration
FROM (`projects`)
LEFT JOIN `users`
ON `users`.`id` = `projects`.`user_id`
LEFT JOIN `users` as users2
ON `users2`.`id` = `projects`.`assignee_id`
LEFT JOIN `tasks` ON `tasks`.`project_id` = `projects`.`id`
GROUP BY `projects`.`id`
ORDER BY `projects`.`created` DESC
Below is my projects table:
Below is my tasks table:
Thanks in advance!
Usually this query will help you.
SELECT p.*, (SELECT SUM(t.time_spent) FROM tasks as t WHERE t.project_id = p.id) as project_fulltime FROM projects as p
In your question, you don't say about users. Do you need users?
You are on right way, maybe your JOINs can't fetch all data.
This query should do it for you.
Note, whenever you do a group by you must include every column that you select from or order by. Some MySql installations don't prevent you from doing this, but in the end it results in an incorrect result set.
As well you should never do a query as part of your SELECT statement, known as a sub-query, as it will result in an equal amount of additional queries in relation to the number of rows returned. So if you got 1,000 rows back, it would result in 1,001 queries instead of 1 query.
SELECT
p.id,
p.description,
p.created,
u.title,
u.firstname,
u.lastname,
a.title assignee_title,
a.firstname assignee_firstname,
a.lastname assignee_lastname,
SUM(t.time_spent) project_duration
FROM
projects p
LEFT JOIN
users u ON
u.id = p.user_id
LEFT JOIN
users a ON
a.id = u.assignee_id
LEFT JOIN
tasks t ON
t.project_id = p.id
GROUP BY
p.id,
p.description,
p.created,
u.title,
u.firstname,
u.lastname,
a.title,
a.firstname,
a.lastname
ORDER BY
p.created DESC
I am running a MySQL query to get all "users" with current orders.
(It is possible for a user to have more than 1 associated orders in the db/query).
However i also want to get the total order value for each user and total order count for each user that is being returned (within the below query).
I could do these calculations in PHP, but feel it is possible and would be neater all done within the same SQL query (if possible).
This is the basic query with no attempt to make the above calculations
SELECT u.UserID, u.UserName,
o.OrdersID, o.OrderProductName, o.OrderProductQT, o.OrderTotalPrice, o.tUsers_UserID, o.tOrderStatus_StatusID, o.OrderDate, o.OrderDateModified, o.OrderVoid, o.tProducts_ProductID,
os.OrderStatusName,
ud.UserDetailsName, ud.UserDetailsPostCode,
p.ProductName, p.ProductImage1
FROM tusers u
INNER JOIN torders o ON o.tUsers_UserID = u.UserID
INNER JOIN torderstatus os ON os.OrderStatus_StatusID = o.tOrderStatus_StatusID
INNER JOIN tuserdetails ud ON ud.tUsers_UserID = u.UserID
LEFT JOIN tproducts p ON p.ProductID = o.tProducts_ProductID
WHERE o.tOrderStatus_StatusID = ?
GROUP BY u.UserID
ORDER BY OrdersID DESC
I have tried various nested select queries, but none of them work (right)
Is what i want to do possible in SQL or should i just do it all in PHP once i have the returned query results?
Any advice is much appreciated
You can embed the slightly modified queries into another query. For instance:
SELECT userid, SUM(orderid) FROM orders GROUP BY userid
and
SELECT userid, SUM(distinct productid)
FROM
orders o
INNER JOIN orderlines ol on ol.orderid = o.orderid
GROUP BY
userid
can be combined to:
SELECT
u.userid
u.fullname,
(SELECT SUM(orderid)
FROM orders o
WHERE o.userid = u.userid) as ORDERCOUNT,
(SELECT SUM(distinct productid)
FROM
orders o
INNER JOIN orderlines ol on ol.orderid = o.orderid
WHERE
o.userid = u.userid) as UNIQUEPRODUCTS
FROM
users u
Note that the latter query will return all users and will return NULL for ORDERCOUNT or UNIQUEPRODUCTS when the subquery doesn't return anything (when a user doesn't have orders). Also, the query will fail when a subquery returns more than 1 row, which should never happen in the example I posted.
i am using this query to fetching products.the product table has 302,716 rows.it is taking too much time to execute around 2-3 minutes.but when i removed order by it takes less time.
SELECT DISTINCT
product.ProductID,
company.CompanyName
FROM
product
INNER JOIN company
ON company.CompanyID = product.CompanyID
LEFT JOIN company_csv_data
ON company.CompanyID = company_csv_data.CompanyID
LEFT JOIN productcategory
ON product.ProductID = productcategory.ProductID
LEFT JOIN category
ON category.CategoryID = productcategory.CategoryID
LEFT JOIN supplier
ON product.supplier = supplier.id
LEFT JOIN template_vouchers tm
ON product.ProductID = tm.voucher_id
WHERE company.turn_on = 1
AND product.ProductEndDate >= CURRENT_DATE
AND turn_off = 1
GROUP BY product.ProductID
ORDER BY clicks DESC,
product.CodeOpen DESC,
product.Online,
product.EntryDate DESC
LIMIT 0, 15
You could improve the query's speed/performance by creating indexes for the columns in the select and where clauses (this will slow down insert, delete and update statements..)
I've got reporting of a user's score everytime it happens. Now I want to show the best score a user has had. The table set up is like this:
Player(id, name)
PlayerHasAchievement(id, playerId,
achievementId)
Achievement(id, type, amount, time)
This is what I have right now:
$query = "SELECT MAX(ach.amount) as amount, p.username, ach.time
FROM achievement as ach
INNER JOIN playerHasAchievement as playAch ON ach.id = playAch.id
INNER JOIN player as p ON p.userId = playAch.userid
WHERE ach.type = 2
GROUP BY amount
ORDER by `amount` DESC
LIMIT $amount";
I tried to select it distinctly but it didn't work. I'm stumped, it's supposed to be so easy! Thanks for reading, I'll be grateful for any help!
The problem is the the ach.time you are getting is not the same row as the MAX(amount). Join another subquery to get the MAX(amount) first.
Note: In the table definitions you posted, playerHasAchievement has a field playerId not userId
SELECT MAX(ach.amount) as amount, p.username, MAX(ach.time) MaxTime
FROM achievement as ach
INNER JOIN playerHasAchievement as playAch ON ach.id = playAch.id
INNER JOIN player as p ON p.userId = playAch.playerId
INNER JOIN (
SELECT playAch.playerId, MAX(ach.amount) as MaxAmount
FROM achievement as ach
INNER JOIN playerHasAchievement as playAch ON ach.id = playAch.id
WHERE ach.type = 2
GROUP BY playAch.playerId
) g ON p.playerId = g.playerId AND ach.amount = g.MaxAmount
WHERE ach.type = 2
GROUP BY p.playerId
ORDER by `amount` DESC
LIMIT $amount";
The reason why we group the outer query, is to avoid ties - say a player had the same score twice.
In your join on line 3 don't you really want
INNER JOIN playerHasAchievement as playAch ON ach.id = playAch.achievementId
and others are correct, you need to group by your non aggregate columns, not the aggregate one.
Assuming your db layout is as specified in the question here is the query I would use.
SELECT ach.amount, p.Name, ach.time
FROM achievement as ach
JOIN playerHasAchievement as playAch ON ach.id=playAch.achievementId
JOIN player AS p ON p.id = playAch.playerId
WHERE ach.type = 2
AND ach.amount = (SELECT MAX(ach.amount)
FROM achievement as ach
JOIN playerHasAchievement as playAch ON ach.id=playAch.achievementId
JOIN player AS p ON p.id = playAch.playerId
WHERE ach.type = 2)
GROUP BY ach.amount
ORDER by ach.time
taking the first result (in case there are multiples of the same score) will give you the high score and the lowest time.
Hope that helps!
You are not using group by appropriately, as you are only grouping by amount.
What about the user name and the time?