I have sql query like this:
SELECT sum(amount) AS sum, incomes_category_assigned_to_users.name AS category_name
FROM incomes
INNER JOIN incomes_category_assigned_to_users on incomes.income_category_assigned_to_user_id = incomes_category_assigned_to_users.id
WHERE (incomes.user_id = :user_id AND date_of_income >= :first_date AND date_of_income <= :second_date)
GROUP BY incomes.income_category_assigned_to_user_id
ORDER BY sum DESC;
The result is the user incomes grouped by the category - displayed as an array.
I would like to add subquery - get these incomes, not grouped, so that the user can expand the field in array and see it in detail.
Thanks for help
MySQL does not support arrays. One method is to put the values into a string:
SELECT SUM(amount) AS sum,
GROUP_CONCAT(amount) as amounts,
icau.name AS category_name
FROM incomes i JOIN
incomes_category_assigned_to_users icau
ON i.income_category_assigned_to_user_id = icau.id
WHERE i.user_id = :user_id AND
date_of_income >= :first_date AND
date_of_income <= :second_date
GROUP BY icau.name
ORDER BY sum DESC;
Note the changes I made to the query:
The tables have reasonable table aliases. They make the query easier to write and to read.
No parentheses are needed in a WHERE clause that just uses AND.
The GROUP BY keys are now consistent with the unaggregated SELECT columns.
Related
Hoping someone can help me out with a small SQL problem.
I have a group of users with a registration_date and an activity_date, that can have many values. Each of those columns are in different tables, users and activty, respectively.
I need to subtract the 2 dates, the registration_date the most recent activity_date. Then I want to be able to average the subtracted dates for all users in the table. And I only want to see the AVG for the users where the TIMEDIFF is >= 90
I've tried to use MAX(activity_date), as in
SELECT activity.user_id, AVG(TIMESTAMPDIFF (day,users.reg_ts, SELECT
MAX(activity.actvy_ts FROM activity))) AS LifetimeAVG
FROM activity JOIN users
ON activity.user_id = users.user_id
WHERE TIMESTAMPDIFF (day,users.reg_ts, activity.actvy_ts) >= 90
GROUP BY activity.user_id
;
but it throws a group error.
ERROR: ER_INVALID_GROUP_FUNC_USE: Invalid use of group function
You cannot use one aggregate function MAX() inside another aggregate function AVG(), because that does not make any sense for a particular "group".
Instead, you will need to do first-level aggregation (MAX), at an inner subquery level (Derived Table), and then use the result-set for further aggregation (AVG):
SELECT Avg(dt.max_diff) AS LifetimeAVG
FROM (SELECT u.user_id,
Timestampdiff (day, u.reg_ts, Max(a.actvy_ts)) AS max_diff
FROM activity AS a
JOIN users AS u
ON u.user_id = a.user_id
GROUP BY u.user_id, u.reg_ts
HAVING max_diff >= 90) AS dt
I am using following query
select
*,
dealer.id As dealerID,
services.id as serviceID
from services
LEFT JOIN dealer
on services.dealer=dealer.id
LEFT JOIN reviews
ON reviews.dealer_id=dealer.id
where services.brand_id = '9' and
services.model_id='107' and
services.petrol > 0
ORDER BY services.total asc ,
AVG(reviews.rating) desc
I have 6 records and it should display 6 records instead its displaying only 1. When i remove AVG(reviews.rating) desc. It display all records.
mysql tables are
services
dealer
brand_id
model_id
petrol
id
total
dealer
id
name
reviews
id
dealer_id
rating
I am not sure where i am doing mistake. If some can help.
avg() is an aggregation function. That is, it takes data from multiple rows and summarizes it.
Without a group by, the query is an aggregation query over all the data. Such a query always returns exactly one row.
Most databases would return an error when you use select *, use an aggregation function, and have no group by. MySQL has a (mis)feature where this syntax is allowed (although on the newest versions, the default settings disallow this).
I'm not sure what you are trying to do, but avg() doesn't make sense in this context. Perhaps this does what you want:
ORDER BY services.total asc, reviews.rating desc
As already mentioned AVG() is aggregate ftn, so I have changed the desc of your order by to include to select the average values.
For future reference:
Providing snippets of raw data also helps. Creating an sql fiddle helps even more
select
*,
dealer.id As dealerID,
services.id as serviceID
from services
LEFT JOIN dealer
on services.dealer=dealer.id
LEFT JOIN reviews
ON reviews.dealer_id=dealer.id
where services.brand_id = '9' and
services.model_id='107' and
services.petrol > 0
ORDER BY services.total asc ,
(SELECT AVG(r2.rating) FROM reviews r2 RIGHT JOIN ON r2.dealer_id=dealer.id) desc
You might try:
SELECT
*,
AVG(c.rating) AS `avg__rating`,
b.id AS dealerID,
a.id AS serviceID
FROM services a
LEFT JOIN dealer b
on a.dealer = b.id
LEFT JOIN reviews c
ON c.dealer_id = b.id
WHERE a.brand_id = '9' and
a.model_id='107' and
a.petrol > 0
GROUP BY a.dealer, a.brand_id, a.model_id, a.petrol, a.id, a.total
ORDER BY a.total asc,
AVG(c.rating) desc
This adds a GROUP BY on the columns in your services table so you will get one row per services/dealer.
I have two tables - results and contestants. Result table cointains
result_id (PK)
resul_contestant (who scored this)
value (how much did he scored)
result_discipline(where he scored this)
contestants table cointains
contestant_id (PK)
contestant_name
contestant_category
What I want to do is to select results for all contestants, but I only want to show one result per contestant - the highest (lowest) one.
So far I managed to do this:
SELECT * FROM contenstants
JOIN results ON result_contestant = contenstant_id
WHERE result_discipline = 1 AND contestant_category = 1
ORDER BY value DESC
GROUP BY contenstant_id;
However, this gives me syntax error. If I delete the GROUP BY line, I got results ordered from highest, but if any of the contestants scored in this discipline more than once, I got all of his scores.
If I delete the ORDER BY line, I got only one result per contestant, but it returns the first record in db, not the highest one.
How to fix this command to be valid? Also, there are some less_is_better disciplines, where I want the lowest score, but as far as I could use the ORDER BY on final query, it should be achieved by replacing DESC with ASC.
Thanks.
Don't use group by. Using select * with group by just doesn't make sense. Instead, use a filter to get the row you want:
SELECT *
FROM contenstants c JOIN
results r
ON r.result_contestant = c.contestant_id
WHERE r.result_discipline = 1 AND c.contestant_category = 1 AND
r.value = (select min(r2.value)
from results r2
where r2.result_contestant = r.result_contestant and
r2.result_discipline = r.result_discipline
)
ORDER BY value DESC;
Note: I'm not sure if you want min() or max() in the subquery.
I'm fairly new to Mysql and need help trying to combine two mysql queries that give a "total" for each "storeid" from the orders total. I'm currently using two queries to get the result:
SELECT storeid, storenum, name FROM store ORDER BY storeid DESC
SELECT SUM((1+0.07125)*qty*discprice) as total FROM items WHERE orderid IN (SELECT orderid FROM orders WHERE store = '".$row['storeid']."' AND date >= '2012-01-01' AND date < '2013-01-01')
I'm running a while loop and running the second query with the "storeid". However, I know I can do this is one query and group by "storeid" and create a total for all stores combined. But I can't figure it out.
Thanks!
SELECT s.storeid, s.storenum, s.name
SUM((1+0.07125)*i.qty*i.discprice) AS total
FROM items AS i
LEFT JOIN orders AS o
ON i.orderid=o.orderid
LEFT JOIN stores AS s
ON o.store=s.storeid
WHERE o.date >= '2012-01-01'
AND o.date < '2013-01-01'
GROUP BY s.storeid, s.storenum, s.name;
The trick is to join the three tables and then use an aggregate function on the items table.
SELECT stores.storeid, stores.storenum, stores.name, SUM((1+0.07125)*items.qty*items.discprice) as total
FROM stores
LEFT JOIN orders ON orders.storeid=stores.storeid AND orders.date>='2012-01-01' AND orders.date<'2013-01-01'
LEFT JOIN items ON items.orderid=orders.orderid
GROUP BY stores.storeid, stores.storenum, stores.name
What this does it this:
It will select every store from the stores table, and sum up the orders in that store. I chose a LEFT JOIN instead of straight JOINs, so that stores without any order in that time span will still show up with a total of NULL.
P.S. I don't have a copy of your database's schema, above SQL query might not actually work as expected - it is just supposed to point you in the right direction.
Here is my data structure
alt text http://luvboy.co.cc/images/db.JPG
when i try this sql
select rec_id, customer_id, dc_number, balance
from payments
where customer_id='IHS050018'
group by dc_number
order by rec_id desc;
something is wrong somewhere, idk
I need
rec_id customer_id dc_number balance
2 IHS050018 DC3 -1
3 IHS050018 52 600
I want the recent balance of the customer with respective to dc_number ?
Thanx
There are essentially two ways to get this
select p.rec_id, p.customer_id, p.dc_number, p.balance
from payments p
where p.rec_id IN (
select s.rec_id
from payments s
where s.customer_id='IHS050018' and s.dc_number = p.dc_number
order by s.rec_id desc
limit 1);
Also if you want to get the last balance for each customer you might do
select p.rec_id, p.customer_id, p.dc_number, p.balance
from payments p
where p.rec_id IN (
select s.rec_id
from payments s
where s.customer_id=p.customer_id and s.dc_number = p.dc_number
order by s.rec_id desc
limit 1);
What I consider essentially another way is utilizing the fact that select rec_id with order by desc and limit 1 is equivalent to select max(rec_id) with appropriate group by, in full:
select p.rec_id, p.customer_id, p.dc_number, p.balance
from payments p
where p.rec_id IN (
select max(s.rec_id)
from payments s
group by s.customer_id, s.dc_number
);
This should be faster (if you want the last balance for every customer), since max is normally less expensive then sort (with indexes it might be the same).
Also when written like this the subquery is not correlated (it need not be run for every row of the outer query) which means it will be run only once and the whole query can be rewritten as a join.
Also notice that it might be beneficial to write it as correlated query (by adding where s.customer_id = p.customer_id and s.dc_number = p.dc_number in inner query) depending on the selectivity of the outer query.
This might improve performance, if you look for the last balance of only one or few rows.
I don't think there is a good way to do this in SQL without having window functions (like those in Postgres 8.4). You probably have to iterate over the dataset in your code and get the recent balances that way.
ORDER comes before GROUP:
select rec_id, customer_id, dc_number, balance
from payments
where customer_id='IHS050018'
order by rec_id desc
group by dc_number