i have a problem concerning a select query in MYSQL
i have two different tables and i want to obtain a certain result
i used COUNT method which gave me only the results (>=1)
But in reality , i want to use all counts with zero included how to do it?
My query is:
SELECT
first.subscriber_id,
second.tag_id,
COUNT(*)
FROM
content_hits first
JOIN content_tag second ON first.content_id=second.content_id
GROUP BY
second.Tag_id,first.Subscriber_id<br>
First table:Content_hits
CONTENT_ID SUBSCRIBER_ID
30 1
10 10
34 4
32 2
40 3
28 3
30 6
31 8
12 3
Second table:Content_tag
CONTENT_ID TAG_ID
1 1
2 1
3 1
4 1
5 1
6 1
7 1
8 1
9 1
10 1
11 2
12 2
13 2
14 2
Result but incomplete For example:Subsrciber6 for tag_id=1 should have a count(*)=0
subscriber_id tag_id COUNT(*)
1 1 4
2 1 7
3 1 2
4 1 1
5 1 3
7 1 2
8 1 1
9 1 1
10 1 3
1 2 2
2 2 3
3 2 2
Now that you have further elaborated on what you actually want to achieve, it can be seen that the problem is much more complex. You actually want all combinations of subscriber_id and tag_id, and then count the number of actual entries in the joined table product. whew. So here goes the SQL:
SELECT combinations.tag_id,
combinations.subscriber_id,
-- correlated subquery to count the actual hits by tag/subscriber when joining
-- the two tables using content_id
(SELECT count(*)
FROM content_hits AS h
JOIN content_tag AS t ON h.content_id = t.content_id
WHERE h.subscriber_id = combinations.subscriber_id
AND t.tag_id = combinations.tag_id) as cnt
-- Create all combinations of tag/subscribers first, before counting anything
-- This will be necessary to have "zero-counts" for any combination of
-- tag/subscriber
FROM (
SELECT DISTINCT tag_id, subscriber_id
FROM content_tag
CROSS JOIN content_hits
) AS combinations
Not sure, but is this what you want?
SELECT first.subscriber_id, second.tag_id, COUNT(*) AS c
FROM content_hits first JOIN content_tag second ON first.content_id=second.content_id
GROUP BY second.Tag_id,first.Subscriber_id HAVING c = 0
Related
Imagine I have the following tables:
Numbers PK
1
2
3
4
5
6
7
8
9
10
Numbers FK 1
Numbers FK 2
1
1
2
1
3
1
4
1
5
1
6
1
7
1
8
1
9
1
10
1
8
8
10
4
7
3
4
9
1
6
3
9
4
6
5
6
I have the following tables: "Numbers PK" as Primary key and another 2 tables that are related one with each other that are foreign keys of Numbers.
I am trying to make a query to select the number(s) from the table "NumbersFK2" that are related with all the numbers of "Numbers PK".
As you can see in this example the solution would be 1 as 1 is related with 1-10 in the tables "Numbers FK1" and "Numbers FK2"
I have tried to solve and after some days I need some help as I don't know how could I do it. I appreciate the help. Thanks
We use dense_rank() to count the Numbers_PK in case they're not consecutive. Then we left join, group by and count(distinct Numbers_PK).
with t3 as (
select Numbers_PK
,dense_rank() over(order by Numbers_PK) as dns_rnk
from t
)
select Numbers_FK_2
from t3 left join t2 on t2.Numbers_FK_1 = t3.Numbers_PK
group by Numbers_FK_2
having count(distinct Numbers_PK) = max(dns_rnk)
Numbers_FK_2
1
Fiddle
I have a database with a table called BOOKINGS containing the following values
main-id place-id start-date end-date
1 1 2018-8-1 2018-8-8
2 2 2018-6-6 2018-6-9
3 3 2018-5-5 2018-5-8
4 4 2018-4-4 2018-4-5
5 5 2018-3-3 2018-3-10
5 1 2018-1-1 2018-1-6
4 2 2018-2-1 2018-2-10
3 3 2018-3-1 2018-3-28
2 4 2018-4-1 2018-4-6
1 5 2018-5-1 2018-5-15
1 3 2018-6-1 2018-8-8
1 4 2018-7-1 2018-7-6
1 1 2018-8-1 2018-8-18
1 2 2018-9-1 2018-9-3
1 5 2018-10-1 2018-10-6
2 5 2018-11-1 2018-11-5
2 3 2018-12-1 2018-12-25
2 2 2018-2-2 2018-2-19
2 4 2018-4-4 2018-4-9
2 1 2018-5-5 2018-5-23
What I need to do is for each main-id I need to find the largest total number of days for every place-id. Basically, I need to determine where each main-id has spend the most time.
This information must then be put into a view, so unfortunately I can't use temporary tables.
The query that gets me the closest is
CREATE VIEW `MOSTTIME` (`main-id`,`place-id`,`total`) AS
SELECT `BOOKINGS`.`main-id`, `BOOKINGS`.`place-id`, SUM(DATEDIFF(`end-date`, `begin-date`)) AS `total`
FROM `BOOKINGS`
GROUP BY `BOOKINGS`.`main-id`,`RESERVATION`.`place-id`
Which yields:
main-id place-id total
1 1 24
1 2 18
1 5 5
2 1 2
2 2 20
2 4 9
3 1 68
3 2 24
3 3 30
4 1 5
4 2 10
4 4 1
5 1 19
5 2 4
5 5 7
What I need is then the max total for each distinct main-id:
main-id place-id total
1 1 24
2 2 20
3 1 68
4 2 10
5 1 19
I've dug through a large amount of similar posts that recommend things like self joins; however, due to the fact that I have to create the new field total using an aggregate function (SUM) and another function (DATEDIFF) rather than just querying an existing field, my attempts at implementing those solutions have been unsuccessful.
I am hoping that my query that got me close will only require a small modification to get the correct solution.
Having hyphen character - in column name (which is also minus operator) is a really bad idea. Do consider replacing it with underscore character _.
One possible way is to use Derived Tables. One Derived Table is used to determine the total on a group of main id and place id. Another Derived Table is used to get maximum value out of them based on main id. We can then join back to get only the row corresponding to the maximum value.
CREATE VIEW `MOSTTIME` (`main-id`,`place-id`,`total`) AS
SELECT b1.main_id, b1.place_id, b1.total
FROM
(
SELECT `main-id` AS main_id,
`place-id` AS place_id,
SUM(DATEDIFF(`end-date`, `begin-date`)) AS total
FROM BOOKINGS
GROUP BY main_id, place_id
) AS b1
JOIN
(
SELECT dt.main_id, MAX(dt.total) AS max_total
FROM
(
SELECT `main-id` AS main_id,
`place-id` AS place_id,
SUM(DATEDIFF(`end-date`, `begin-date`)) AS total
FROM BOOKINGS
GROUP BY main_id, place_id
) AS dt
GROUP BY dt.main_id
) AS b2
ON b1.main_id = b2.main_id AND
b1.total = b2.max_total
MySQL 8+ solution would be utilizing the Row_Number() functionality:
CREATE VIEW `MOSTTIME` (`main-id`,`place-id`,`total`) AS
SELECT b.main_id, b.place_id, b.total
FROM
(
SELECT dt.main_id,
dt.place_id,
dt.total
ROW_NUMBER() OVER (PARTITION BY dt.main_id
ORDER BY dt.total DESC) AS row_num
FROM
(
SELECT `main-id` AS main_id,
`place-id` AS place_id,
SUM(DATEDIFF(`end-date`, `begin-date`)) AS total
FROM BOOKINGS
GROUP BY main_id, place_id
) AS dt
GROUP BY dt.main_id
) AS b
WHERE b.row_num = 1
Currently I am honestly at loss what I am doing wrong. It is a rather simple query I think.
Tables:
operations:
id processedon clientid
1 2018-01-01 9
2 2018-03-16 9
3 2018-04-21 9
4 2018-04-20 9
5 2018-05-09 9
items:
id operation_id quantity unitprice
1 1 10 2
2 1 5 3
3 2 20 4
4 3 10 2
5 4 8 4
6 4 10 4
7 5 2 2
The expected result of the operation/query is:
month total_value
1 35
3 80
4 92
5 4
That is quantity * unitprice based. For some reason, it only returns month=4
SELECT
month(`operations`.`processedon`) AS `month`,
SUM((`items`.`quantity` * `items`.`unitprice`)) AS `total_value`
FROM `items`
INNER JOIN `operations` ON (`items`.`operation_id` = `operations`.`id`)
GROUP BY 'month'
ORDER BY 'month'
According to the info provided the join should be
INNER JOIN operations ON items.operation_id = operations.id
Eg
SELECT
month(`operations`.`processedon`) AS `month`,
SUM((`items`.`quantity` * `items`.`unitprice`)) AS `total_value`
FROM `items`
INNER JOIN `operations` ON `items`.`operation_id` = `operations`.`id`
GROUP BY month(`operations`.`processedon`)
ORDER BY `month`
There is no efficiency gain by using a column alias in the group by clause, I prefer to avoid using them except perhaps in the order by clause.
The following query will give you the required answer
SELECT
month(`operations`.`processedon`) AS `month`,
SUM((`items`.`quantity` * `items`.`unitprice`)) AS `total_value`
FROM items
INNER JOIN operations ON (items.operation_id = operations.id)
GROUP BY month(operations.processedon)
ORDER BY month(operations.processedon)
You need to specify month correctly since it is not an existing column.
You'll get the following result
month total_value
1 35
3 80
4 92
5 4
I have a query like below, it is working fine but not optimized, since it takes 1.5 sec to run. How to make this to an optimized result?
select h.keyword_id,
( select count(DISTINCT(user_id)) from history where category_id = 6
and h.keyword_id=keyword_id group by keyword_id ) as cat_6,
( select count(DISTINCT(user_id)) from history where category_id = 7
and h.keyword_id = keyword_id group by keyword_id ) as cat_7
from
history h group by h.keyword_id
History table
his_id keyword_id category_id user_id
1 1 6 12
2 1 6 12
3 1 7 12
4 1 7 12
5 2 6 13
6 2 6 13
7 2 7 13
8 3 6 13
Result:
keyword_id cat_6 cat_7
1 2 2 (unique users)
2 2 1
3 1 0
You can rewrite your query like this:
select h.keyword_id,
count(distinct if(category_id = 6, user_id, null)) as cat_6,
count(distinct if(category_id = 7, user_id, null)) as cat_7
from
history h
group by h.keyword_id
Your desired result based on the sample data is by the way false. In each keyword_id there's always just one distinct user_id.
you can see the query in action in an sqlfiddle here
For more optimization, you'd have to post the result of show create table history and the output of explain <your_query>;
I'm trying to get the query below to show for each item for each store the amount of each of 4 items we have.
It works great, and I created the temporary table to try to increase speed but my problem is that if the table has no rows for a certain product that product does not show up at all.
I'd like to show all four products(prodNo) regardless of if there is actually any of rows for that specific store.
I researched this site and could not find something similar enough for me to figure it out.
CREATE TEMPORARY TABLE IF NOT EXISTS temp_invoice_dates AS
(
SELECT Invoice_detail.del_date,invoice_Detail.StoreNo,mast_stores.SDesc, invoice_Detail.ProdNo,sold_qty,retn_price,retn_qty,sold_price FROM Invoice_detail
LEFT JOIN mast_stores on invoice_detail.StoreNO=mast_stores.Snum
LEFT JOIN invoice on invoice_detail.Del_Date=invoice.Del_Date and invoice_detail.Invoice_No=invoice.Invoice_No
WHERE Cnum IN ('200','210') AND invoice_detail.Del_Date >= "2016-03-01" AND invoice_detail.Del_Date < "2016-04-01"
);
SELECT
temp_invoice_dates.StoreNo,
temp_invoice_dates.SDesc,
DATE_FORMAT(temp_invoice_dates.Del_Date,'%Y') as Year,
DATE_FORMAT(temp_invoice_dates.Del_Date,'%M') as Month,
temp_invoice_dates.ProdNo,
mast_items.IDesc,
SUM(sold_qty) as TotalIn,
SUM(retn_qty) as TotalOut,
ROUND(SUM((sold_qty*sold_price)-(retn_qty*retn_price)),2) as NetSales,
CONCAT(ROUND(SUM(retn_qty)/SUM(sold_qty),2)*100,'%') as StalePerc
FROM mast_Items
LEFT JOIN temp_invoice_dates on temp_invoice_dates.ProdNo=mast_items.Inum
WHERE mast_items.Inum in ('3502','3512','4162','4182')
GROUP BY temp_invoice_dates.StoreNo, ProdNo
ORDER BY temp_invoice_dates.StoreNo, ProdNo;
Drop table temp_invoice_dates;
Results are similar to:
StoreNo Product Count....
1 1 1
1 2 5
1 3 2
1 4 1
2 1 14
2 2 1
2 4 4
3 2 33
3 3 3
Where as I'd like it to be
StoreNo Product Count ....
1 1 1
1 2 5
1 3 2
1 4 1
2 1 14
2 2 1
2 3 0
2 4 4
3 1 0
3 2 33
3 3 3
3 4 0
Something like this should work.
SELECT sp.StoreNo, sp.ProdNo
, ...stuff...
, sp.IDesc, sp.SDesc
, ...more stuff...
FROM (
SELECT i.Inum AS ProdNo, s.Snum AS StoreNo
, i.IDesc, s.SDesc
FROM mast_Items AS i, mast_stores AS s
WHERE i.Inum IN ('3502','3512','4162','4182')
) AS sp
LEFT JOIN temp_invoice_dates AS tid
ON sp.ProdNo = tid.ProdNo
AND sp.StoreNo = tid.StoreNo
GROUP BY sp.StoreNo, sp.ProdNo
ORDER BY sp.StoreNo, sp.ProdNo
;
Normally I recommend against cross joins (as seen in the subquery) but in this case it is exactly what is needed. If the query is slow, you can instead insert the subquery results into a temp table beforehand, index that, and then use the temp table in place of the subquery.
(Edit: should use sp fields when available for grouping and results)