Grab top row from GROUP BY - mysql

Going off of my last question: Complex Grouping in SQL Query…
In each grouping, I'd like to grab only the row with the highest 'step' value.
This is the query we came up with in the last question:
SELECT a.*, b.*
FROM (
SELECT request_id
FROM tableA
GROUP BY request_id
HAVING MAX(page_views) <= 0 AND MAX(step) <= 2
) AS sumQ
INNER JOIN tableA AS a ON sumQ.request_id = a.request_id
INNER JOIN tableB AS b ON a.request_id = b.id
That returns:
id request_id page_views step name phone
----------------------------------------------------------------
8 3 0 0 Jacob Clark 434-343-434
9 3 0 1 Jacob Clark 434-343-434
10 4 0 0 Alex Smith 222-112-2112
11 4 0 1 Alex Smith 222-112-2112
12 4 0 2 Alex Smith 222-112-2112
Which is what I wanted, however, I realized that in each group (group by request_id) I only need the row with the highest 'step' value. How can I modify my existing query to return only:
id request_id page_views step name phone
----------------------------------------------------------------
9 3 0 1 Jacob Clark 434-343-434
12 4 0 2 Alex Smith 222-112-2112
?

Then include step in the logic:
SELECT a.*, b.*
FROM (SELECT request_id, MAX(step) as maxstep
FROM tableA
GROUP BY request_id
HAVING MAX(page_views) <= 0 AND MAX(step) <= 2
) sumQ INNER JOIN
tableA a
ON sumQ.request_id = a.request_id AND
sumQ.maxstep = a.step INNER JOIN
tableB b
ON a.request_id = b.id;

Have you tried setting an ORDER BY on the step field and then take the TOP record?
SELECT a.*, b.*
FROM (
SELECT TOP 1 request_id
FROM tableA
GROUP BY request_id
HAVING MAX(page_views) <= 0 AND MAX(step) <= 2
ORDER BY step DESC
) AS sumQ
INNER JOIN tableA AS a ON sumQ.request_id = a.request_id
INNER JOIN tableB AS b ON a.request_id = b.id

Related

select rows with condition in other rows

I want select rows from my table with last status_Id if there is a row with status_Id = 2 for that rows
ticketStatus_Id ticket_Id status_Id
======================================
1 1 1
2 1 2 -
3 1 3 *
4 2 1
5 3 1
6 3 2 - *
7 4 1
8 4 2 -
9 4 3
10 4 4 *
I want select just rows 3, 6, 10. there are another rows with status_Id = 2 (rows 2, 6, 8) for that ticket_Id,
In other word How to select rows 3,6,10 with ticket_Id =1,3,4 that there are another row with these ticket_Ids and status_Id=2 (rows 2,6,8)
If you want the complete row, then I would view this as exists:
select t.*
from t
where exists (select 1
from t t2
where t2.ticket_id = t.ticket_id and t2.status_id = 2
) and
t.status_Id = (select max(t2.status_id)
from t t2
where t2.ticket_id = t.ticket_id
);
If you just want the ticket_id and status_id (and not the whole row), I would recommend aggregation:
select ticket_id, max(status_id)
from t
group by ticket_id
having sum(status_id = 2) > 0;
In your case, ticketStatus_Id seems to increase with status_id, so you can use:
select max(ticketStatus_Id) as ticketStatus_Id, ticket_id, max(status_id) as Status_Id
from t
group by ticket_id
having sum(status_id = 2) > 0;
First, for each ticket we get the row with the highest status. We can do this with a self-join. Each row is joined with the row with the next highest status. We select the rows which have no higher status, those will be the highest. Here's a more detailed explanation.
select ts1.*
from ticket_statuses ts1
left outer join ticket_statuses ts2
on ts1.ticket_Id = ts2.ticket_Id
and ts1.status_Id < ts2.status_Id
where ts2.ticketStatus_Id is null
3 1 3
4 2 1
6 3 2
10 4 4
11 5 3
Note that I've added a curve-ball of 11, 5, 3 to ensure we only select tickets with a status of 2, not greater than 2.
Then we can use that as a CTE (or subquery if you're not using MySQL 8) and select only those tickets who have a status of 2.
with max_statuses as (
select ts1.*
from ticket_statuses ts1
left outer join ticket_statuses ts2
on ts1.ticket_Id = ts2.ticket_Id
and ts1.status_Id < ts2.status_Id
where ts2.ticketStatus_Id is null
)
select ms.*
from max_statuses ms
join ticket_statuses ts
on ms.ticket_id = ts.ticket_id
and ts.status_id = 2;
3 1 3
6 3 2
10 4 4
This approach ensures we select the complete rows with the highest statuses and any extra data they may contain.
dbfiddle
This is basicaly a "last row per group" problem. You will find some solutions here. My prefered solution would be:
select t.*
from (
select max(ticketStatus_Id) as ticketStatus_Id
from mytable
group by ticket_Id
) tmax
join mytable t using(ticketStatus_Id)
The difference in your question is that you have a condition requiring a specific value within the group. This can be solved with a JOIN within the subquery:
select t.*
from (
select max(t1.ticketStatus_Id) as ticketStatus_Id
from mytable t2
join mytable t1 using(ticket_Id)
where t2.status_Id = 2
group by t2.ticket_Id
) tmax
join mytable t using(ticketStatus_Id)
Result:
| ticketStatus_Id | ticket_Id | status_Id |
| --------------- | --------- | --------- |
| 3 | 1 | 3 |
| 6 | 3 | 2 |
| 10 | 4 | 4 |
View on DB Fiddle
A solution using window functions could be:
select ticketStatus_Id, ticket_Id, status_Id
from (
select *
, row_number() over (partition by ticket_Id order by ticketStatus_Id desc) as rn
, bit_or(status_Id = 2) over (partition by ticket_Id) > 0 as has_status2
from mytable
) x
where has_status2 and rn = 1
A quite expressive way is to use EXISTS and NOT EXISTS subquery conditions:
select t.*
from mytable t
where exists (
select *
from mytable t1
where t1.ticket_Id = t.ticket_Id
and t1.status_Id = 2
)
and not exists (
select *
from mytable t1
where t1.ticket_Id = t.ticket_Id
and t1.ticketStatus_Id > t.ticketStatus_Id
)
SELECT a.*
FROM t a
JOIN
(
SELECT ticket_id, MAX(status_id) max_status_id
FROM t
WHERE status_id >= 2
GROUP BY ticket_id
) b
ON a.ticket_id = b.ticket_id
AND a.status_id = b.max_status_id;
SELECT
MAX(m1.ticketstatus_Id) as ticket_status,
m1.ticket_Id as ticket,
MAX(m1.status_Id) as status
FROM mytable m1
WHERE
m1.ticket_Id in (select m2.ticket_Id from mytable m2 where m2.ticket_Id=m1.ticket_Id and m2.status_Id=2)
GROUP BY m1.ticket_Id

Mysql group_concat for count in sub query using parent filed is not allowed

I need to process album count for each of the country per artist; however, I have a problem once I do group_concat for count in mysql, I search a bit in stackoverflow, I found I have to do sub select for group_concat. The problem is once I do the sub select in from I can not use a.id from the parent from filed table. I got error like following Unknown column 'a.id' in 'where clause'
This is the query:
SELECT a.seq_id, a.id
(SELECT GROUP_CONCAT(cnt) AS cnt FROM (
SELECT CONCAT_WS('-', mgr.country_code, count(mgr.media_id)) AS cnt
FROM music_album_artists AS ma
JOIN media_geo_restrict AS mgr ON ma.album_id = mgr.media_id
WHERE ma.artist_id = a.id
GROUP BY mgr.country_code
) count_table
) AS album_count
FROM music_artist AS a
WHERE a.seq_id > 0 and a.seq_id < 10000
The sample data in tables:
music_artists:
seq_id id name
1 1 Hola
2 2 Vivi
music_album_artists:
id artist_id album_id
1 1 1
2 1 2
3 1 5
4 1 10
5 2 2
6 2 10
6 2 1
media_geo_restrict:
album_id country_code
1 BE
1 CA
1 DE
1 US
2 CH
2 CA
2 CH
5 DE
10 US
The result I would like to have
seq_id id album_count
1 1 BE--1,CA--2,CH--1,DE--1,US--1
2 2 CA--1,US--2,CH--1
Here is what you need:
select seq_id, id, group_concat(concat(country_code, '--', qtd))
from (
select ma.seq_id, ma.id,
mgr.country_code, count(*) qtd
from music_artists ma
inner join music_album_artists maa
on ma.id = maa.artist_id
inner join media_geo_restrict mgr
on maa.album_id = mgr.album_id
where ma.seq_id > 0 and ma.seq_id < 10000
group by ma.seq_id, ma.id, ma.name,
mgr.country_code
) tb
group by seq_id, id
Here is the working sample: http://sqlfiddle.com/#!9/ff8b5/8
Try this and tell me:
SELECT a.seq_id, a.id, GROUP_CONCAT(cnt) AS cnt
FROM music_artist AS a,
(
SELECT ma.artist_id, CONCAT_WS('-', mgr.country_code, count(mgr.media_id)) AS cnt
FROM music_album_artists AS ma
JOIN media_geo_restrict AS mgr ON ma.album_id = mgr.album_id
GROUP BY mgr.country_code
) AS count_table
WHERE a.seq_id > 0 and a.seq_id < 10000
and a.id=count_table.artist_id
group by a.id

Mysql Update Query for sample table

I have 1 table called sample and it has 3 columns.
id customer default_address
1 1 0
2 1 0
3 1 0
4 1 0
5 2 0
6 2 0
7 3 0
8 3 0
9 2 0
10 2 0
Here I want to group by customer and update first default address should be 1 and rest all for 0 for every customer. How to do it mysql query?
Thanks
UPDATE tb a
LEFT JOIN
(
SELECT customer, MIN(id) id
FROM tb
GROUP BY customer
) b ON a.customer = b.customer AND
a.ID = b.ID
SET a.default_address = b.ID IS NOT NULL
SQLFiddle Demo
UPDATE sample
LEFT JOIN
(SELECT MIN(id) id,customer
FROM sample
GROUP BY customer) t ON sample.customer=t.customer
SET default_address="1"
WHERE sample.id=t.id;
This should work.
Update Table1
INNER JOIN (Select Min(`id`) as MinID,`customer`
From Table1 Group by `customer`) t2
SET Table1.`default_address` = 1
WHERE Table1.`id` = t2.MinID;
SAMPLE FIDDLE

SQL: finding differences between rows

I want to count how many times each user has rows within '5' of eachother.
For example, Don - 501 and Don - 504 should be counted, while Don - 501 and Don - 1600 should not be counted.
Start:
Name value
_________ ______________
Don 1235
Don 6012
Don 6014
Don 6300
James 9000
James 9502
James 9600
Sarah 1110
Sarah 1111
Sarah 1112
Sarah 1500
Becca 0500
Becca 0508
Becca 0709
Finish:
Name difference_5
__________ _____________
Don 1
James 0
Sarah 2
Becca 0
Use the ABS() function, in conjunction with a self-join in a subquery:
So, something like:
SELECT name, COUNT(*) / 2 AS difference_5
FROM (
SELECT a.name name, ABS(a.value - b.value)
FROM tbl a JOIN tbl b USING(name)
WHERE ABS(a.value - b.value) BETWEEN 1 AND 5
) AS t GROUP BY name
edited as per Andreas' comment.
Assuming that each name -> value pair is unique, this will get you the count of times the value is within 5 per name:
SELECT a.name,
COUNT(b.name) / 2 AS difference_5
FROM tbl a
LEFT JOIN tbl b ON a.name = b.name AND
a.value <> b.value AND
ABS(a.value - b.value) <= 5
GROUP BY a.name
As you'll notice, we also have to exclude the pairs that are equal to themselves.
But if you wanted to count the number of times each name's values came within 5 of any value in the table, you can use:
SELECT a.name,
COUNT(b.name) / 2 AS difference_5
FROM tbl a
LEFT JOIN tbl b ON NOT (a.name = b.name AND a.value = b.value) AND
ABS(a.value - b.value) <= 5
GROUP BY a.name
See the SQLFiddle Demo for both solutions.
Because the OP also wants de zero counts, we'll need a self- left join. Extra logic is needed if one person has two exactly the same values, these should also be counted only once.
WITH cnts AS (
WITH pair AS (
SELECT t1.zname,t1.zvalue
FROM ztable t1
JOIN ztable t2
ON t1.zname = t2.zname
WHERE ( t1.zvalue < t2.zvalue
AND t1.zvalue >= t2.zvalue - 5 )
OR (t1.zvalue = t2.zvalue AND t1.ctid < t2.ctid)
)
SELECT DISTINCT zname
, COUNT(*) AS znumber
FROM pair
GROUP BY zname
)
, names AS (
SELECT distinct zname AS zname
FROM ztable
GROUP BY zname
)
SELECT n.zname
, COALESCE(c.znumber,0) AS znumber
FROM names n
LEFT JOIN cnts c ON n.zname = c.zname
;
RESULT:
DROP SCHEMA
CREATE SCHEMA
SET
CREATE TABLE
INSERT 0 14
zname | znumber
-------+---------
Sarah | 3
Don | 1
Becca | 0
James | 0
(4 rows)
NOTE: sorry for the CTE, I had not seen th mysql tag,I just liked the problem ;-)
SELECT
A.Name,
SUM(CASE WHEN (A.Value < B.Value) AND (A.Value >= B.Value - 5) THEN 1 ELSE 0 END) Difference_5
FROM
tbl A INNER JOIN
tbl B USING(Name)
GROUP BY
A.Name

mySQL - GROUP BY but get the most recent row

I've got a budget table:
user_id product_id budget created
-----------------------------------------------------------------
1 1 300 2011-12-01
2 1 400 2011-12-01
1 1 500 2011-12-03
2 2 400 2011-12-04
I've also got a manager_user table, joining a manager with the user
user_id manager_id product_id
------------------------------------
1 5 1
1 9 2
2 5 1
2 5 2
3 5 1
What I'd like to do is grab each of the user that's assigned to Manager #5, and also get their 'budgets'... but only the most recent one.
Right now my statement looks like this:
SELECT * FROM manager_user mu
LEFT JOIN budget b
ON b.user_id = mu.user_id AND b.product_id = mu.product_id
WHERE mu.manager_id = 5
GROUP BY mu.user_id, mu.product_id
ORDER BY b.created DESC;
The problem is it doesn't pull the most recent budget. Any suggestions? Thanks!
To accomplish your task you can do as follows:
select b1.user_id,
b1.budget
from budget b1 inner join (
select b.user_id,
b.product_id,
max(created) lastdate
from budget b
group by b.user_id, b.product_id ) q
on b1.user_id=q.user_id and
b1.product_id=q.product_id and
b1.created=q.lastdate
where b1.user_id in
(select user_id from manager_user where manager_id = 5);
I'm assuming here that your (user_id, product_id, created) combination is unique.
For what it's worth, here's the code that returned what I was looking for:
SELECT DISTINCT(b1.id),mu.user_id,mu.product_id,b1.budget,b1.created
FROM budget b1
INNER JOIN (
SELECT b.user_id, b.product_id, MAX(created) lastdate
FROM budget b
GROUP BY b.user_id, b.product_id) q
ON b1.user_id=q.user_id AND
b1.product_id=q.product_id AND
b1.created=q.lastdate
RIGHT JOIN manager_user mu
ON mu.user_id = b1.user_id AND
mu.product_id = b1.product_id
WHERE mu.manager_id = 5;
Thanks for the help Andrea!