This is my customer table.
I want to group by emp_id alongwith the count. But Group By gets the 'first' record and not the 'newest' one.
I have tried various queries, like this
SELECT id, emp_id, COUNT( * ) AS count, created_at
FROM customer c
WHERE created_at = (
SELECT MAX( created_at )
FROM customer c2
WHERE c2.emp_id = c.emp_id
)
GROUP BY emp_id
ORDER BY created_at DESC
LIMIT 0 , 30
But cannot get the count. Please help.
Edit: this answer doesn't help to obtain count
Try joining to a subquery:
SELECT c1.id, c1.emp_id, c1.created_at, c2.cnt
FROM customer c1
INNER JOIN
(
SELECT emp_id, MAX(created_at) AS max_created_at, COUNT(*) AS cnt
FROM customer
GROUP BY emp_id
) c2
ON c1.emp_id = c2.emp_id AND c1.created_at = c2.max_created_at;
please try this
SELECT cust1.id, cust1.emp_id, cust1.created_at, cust2.cnt
FROM customer cust1
INNER JOIN
(
SELECT emp_id, MAX(created_at) AS max_created_at, COUNT(*) AS count
FROM customer
GROUP BY emp_id
) cust2
ON cust1.emp_id = cust2.emp_id AND cust1.created_at = cust2.max_created_at;
Related
How can i solve this question of hackerrank. I am quite confused an unable to move forward with this.
here is what i have tried
SELECT DISTINCT ACTIVITY FROM FRIENDS,
SELECT max(ACTIVITY) AS M
WHERE M = (SELECT NAME FROM Activities);
You can use window functions if your mysql version is 8 or above
select activity from (select activity, count(*) as cnt,
max(count(*)) over () as maximum_cnt,
min(count(*)) over () as minimum_cnt
from friends group by activity) mytable
where cnt not in (maximum_cnt, minimum_cnt);
I solved this using mysql
select activity
from
(select activity, count(activity) as cnt
from friends
group by activity
having cnt <> (select count(activity) from friends group by activity order by count(activity) limit 1)
and
cnt <> (select count(activity) from friends group by activity order by count(activity) desc limit 1)
) as x;
I like to solve tasks like this with left join and checking NULL:
SELECT
ACTIVITY,
SUM(1) AS Total
INTO #ActivityCount
FROM FRIENDS
GROUP BY ACTIVITY
SELECT
ActivityCount.ACTIVITY
FROM #ActivityCount
LEFT JOIN (SELECT MAX(ActivityCount.Total) AS Total FROM ActivityCount) AS MaxTotal
ON ActivityCount.Total = MaxTotal.Total
LEFT JOIN (SELECT MIN(ActivityCount.Total) AS Total FROM ActivityCount) AS MinTotal
ON ActivityCount.Total = MinTotal.Total
WHERE
MaxTotal.Total IS NULL
AND MinTotal.Total IS NULL
Here is what i did
Select ACTIVITY from Friends
group by ACTIVITY
having count(ACTIVITY) <> (select count1 from (select count(ACTIVITY)
count1 from Friends
group by (ACTIVITY)
order by count1 asc)
where rownum <= 1) and count(ACTIVITY) <> (select count2 from (select count(ACTIVITY) count2 from Friends group by (ACTIVITY) order by count2 desc) where rownum <= 1);
with temp as
(
select activity, count(id) as act_count from friends
group by activity
)
select activity from temp
where act_count not in (select max(act_count) from temp)
and act_count not in (select min(act_count) from temp);
I have a History table that represents messages that are stored by some sort of chat program.
It has a user id, message & datetime. (specified on: http://sqlfiddle.com/#!9/49fcefb/5)
Now, what I want is to have a result which contains:
The max amount of messages typed by date
What user has the most messages and howmany messages this user typed)
I got it working, but I find the query rather slow, I think its because of the last GROUP BY (GROUP BY b.cnt) as this will group over all the records found.
Query:
SELECT b.cnt as dayCount, a.cnt as userCount, a.userid as userId, b.date
FROM (
select date_added as date, user_id as userid, count(*) as cnt from history group by userid, day(date_added),month(date_added),year(date_added)
) a
INNER JOIN (
select date_added as date, count(*) as cnt from history group by day(date_added),month(date_added),year(date_added)
) b ON year(a.date) = year(b.date)
AND month(a.date) = month(b.date)
AND day(a.date) = day(b.date)
GROUP BY b.cnt
ORDER BY dayCount desc, userCount desc limit 10;
Can someone advice me on how to solve this? Maybe with another sort of query?
Thanks in advance!
You can try using windows function with Subquery to get the same result.
select SQ.daycount,SQ.usercount,SQ.user_id, SQ.date1 from (
select sum(count(Message)) over (partition by date(date_added)) as daycount, --to get max amount of msg by date
max(count(Message)) over (partition by date(date_added)) as maxuser, -- to identify user with most msg
count(Message) as usercount,
date(date_added) as date1,user_id from history
group by date1,user_id ) SQ
where SQ.usercount=SQ.maxuser
Check the Fiddle here
seems you are joining with wrong criteria.
first table is getting the # of users, 2nd table is getting the #of days per user_id. see dbfiddle
SELECT b.cnt as dayCount, a.cnt as userCount, a.userid as userId, b.date
FROM (
select
user_id as userid
, count(*) as cnt
from history
group by userid
) a
LEFT JOIN (
select cast(date_added as date) as date
, count(*) as cnt
, user_id as userid
from history
group by cast(date_added as date)
) b ON a.userid = b.userid
ORDER BY dayCount desc, userCount desc limit 10;
I wrote the following query to return the the records with the latest date.
select fs.company_id, max(fs.create_dt) as latestcreatedate
from field_sale fs
group by fs.company_id
order by fs.company_id
The query all works fine. But I need to retrieve the record with all related columns attached to it. Such as, id, title, desc and etc.
How can I retrieve the records with its corresponding columns?
Couple ways of doing so :
-- 1.
SELECT a.*
FROM field_sale a
INNER JOIN
(
select fs.company_id, max(fs.create_dt) as latestcreatedate
from field_sale fs
group by fs.company_id
)b
ON b.company_id = a.company_id AND b.latestcreatedate = a.create_dt
order by a.company_id;
-- 2.
SELECT b.* FROM
(
SELECT a.* , ROW_NUMBER()
OVER (PARTITION BY a.company_id ORDER BY a.create_dt DESC)
AS rn
FROM field_sale a
)b WHERE b.rn = 1
ORDER BY company_id
WITH t AS (
SELECT fs.company_id,
fs.create_dt AS latestcreatedate,
id,
title,
etc,
ROW_NUMBER() OVER ( PARTITION BY fs.company_id ORDER BY fs.create_dt DESC ) AS rowNum
FROM field_sale fs
)
SELECT t.company_id,
t.latestcreatedate,
t.id,
t.title,
t.etc
FROM t
WHERE t.rowNum = 1
ORDER BY t.company_id
I'm not able to use JOINS and group-by together:
I searched for this...but I didn't find the solution..Problem is as below:
I have two tables, first is main_table with fields eid, name, status
Second table is followups with fields fid, eid, last_date, remarks, and next_date
Second table is used to store followup details of clients (client details stored in main_table) and i want to get last followup record for each client with selected date period (from_date to to_date) and sort by next_date in descending order.
i used the below query but not working
SELECT *
FROM main_table as MT
JOIN followups as MF on MT.eid=MF.eid
WHERE MT.status='open' AND MF.NDate<='2012-12-07'
GROUP BY MF.eid
ORDER BY MF.next_date DESC
thanks in advance...guys
Try This
SELECT * FROM main_table AS MT
LEFT JOIN (SELECT * FROM (SELECT * FROM followups ORDER BY next_date DESC) AS A GROUP BY eid) AS MF ON MT.eid=MF.eid
WHERE MT.status='open'
AND MF.NDate<='2012-12-07';
You can try something like this:
select m.eid,
m.name,
m.status,
f1.last_date,
f1.remarks,
f1.next_date
from maintable m
left join
(
select max(last_date) maxLast, eid
from followups
where last_date between from_date and to_date
group by eid
) f
on m.eid = f.eid
left join followups f1
on f.maxLast = f1.last_date
and f.eid = f1.eid
where m.status='open'
and f1.next_date<='2012-12-07'
order by f1.next_date desc
Try this:
SELECT * FROM main_table AS MT
LEFT JOIN (SELECT * FROM (SELECT * FROM followups WHERE NDate<='2012-12-07' ORDER BY next_date DESC) AS A GROUP BY eid) AS MF ON MT.eid=MF.eid
WHERE MT.status='open';
I have the following tables:
content: content_id, user_id, post_date
comment: comment_id, user_id, comment_date
How can I get a count of active unique users grouped by month and year?
Active would mean that the user either posted or commented in that given month.
SELECT
T.action_year,
T.action_month,
COUNT(T.user_id) active_users
FROM
(
SELECT DISTINCT user_id, YEAR(post_date) action_year, MONTH(post_date) action_month FROM content
UNION
SELECT DISTINCT user_id, YEAR(comment_date) action_year, MONTH(comment_date) action_date FROM comment
) T
GROUP BY
T.action_year,
T.action_month
ORDER BY
T.action_year ASC,
T.action_month ASC
this is not tested.
select count(table1.user_id), table1.user_id
from table1 table2
where table1.user_id = table2.user_id
And table2.comment_date like 'may'
Try this
select TO_CHAR(order_dt,'MON-YYYY'), count(distinct User_ID ) cnt from [orders]
where User_ID in
(select User_ID from
(select a.User_ID from [orders] a,
(select a.User_ID,count (a.order_dt) from [orders] a
where a.order_dt > (select max(b.order_dt)-365 from [orders] b where a.User_ID=b.User_ID)
group by a.User_ID
having count(order_dt)>1) b
where a.User_ID=b.User_ID) a
)
group by TO_CHAR(order_dt,'MON-YYYY');