I am having trouble with a query. This is taken from a similar query where i count number of rows per month.
I want to count all rows for each day of the last week and display the day name and a count. If there are no rows for that day, display zero.
I know the UNIONS won't work but i don't know what to replace it with.
At the moment it get the last 7 days but the day name is NULL
SELECT DAYNAME(STR_TO_DATE(Days.ID, '%a')) AS `day`, COUNT(`returns`.list_date) AS `total`
FROM
(
SELECT 1 as ID UNION SELECT 2 as ID UNION SELECT 3 as ID UNION SELECT 4 as ID
UNION
SELECT 5 as ID UNION SELECT 6 as ID UNION SELECT 7 as ID
) as Days
WHERE (list_date >= DATE_SUB(NOW(), INTERVAL 1 WEEK))
GROUP BY Days.id
UPDATE:
I have created a SQL fiddle showing the code output from #Gordon Linoff answer below which doesn't get the counted rows
http://sqlfiddle.com/#!9/969463/1
One method for doing what you want is a LEFT JOIN:
SELECT DAYNAME(DATE_SUB(CURDATE(), INTERVAL Days.n DAY)) AS `day`,
COUNT(r.list_date) AS `total`
FROM (SELECT 1 as n UNION ALL SELECT 2 as n UNION ALL
SELECT 3 as n UNION ALL SELECT 4 as n UNION ALL
SELECT 5 as n UNION ALL SELECT 6 as n UNION ALL
SELECT 7 as n
) Days LEFT JOIN
returns r
ON r.list_date = DATE_SUB(CURDATE(), INTERVAL Days.n DAY))
GROUP BY Days.n
ORDER BY Days.n;
Some notes:
Use UNION ALL instead of UNION, unless you have a good reason for incurring the overhead of removing duplicates.
This assumes that returns.list_date is actually a date, because it uses = rather than >=.
The use of now() and >= is a bit confusing, because now() has a time component, which you generally want to ignore.
Related
My table currently has 21000 records, it's daily updated and almost 300 entries are inserted. Now, what I want is to have a query which will fetch the counts of elements that my table had for the previous 10 days, so it returns:
26000
21300
21000
etc
Right now, I wrote this:
"SELECT COUNT(*) from tbl_task where `task_start_time` < '2020-12-01'"
And it returns 21000 but only for 1 day. I want by query to return records according to 10 days.
However, this does it for only 1 day.
edit : database flavor is mysql and date column is date not datetime
The most efficient method may be aggregation and cumulative sums:
select date(task_start_time) as dte, count(*) as cnt_on_day,
sum(count(*)) over (order by date(task_start_time)) as running_cnt
from tbl_task
group by dte
order by dte desc
limit 10;
This returns the last 10 days in the data. You can easily adjust to more days if you like -- in fact all of them -- without much trouble.
I don't know if I'm wrong, but could you not simple add a GROUP BY - statement? Like:
"SELECT COUNT(*) from tbl_task where `task_start_time` < '2020-12-01' GROUP
BY task_start_time"
EDIT:
This should only work if task_start_time is a date, not if it is a datetime
EDIT2:
If it is a datetime you could use the date function:
SELECT COUNT(*) from tbl_task where `task_start_time` < '2020-12-01' GROUP
BY DATE(task_start_time)
You can use UNION ALL and date arithmetic.
SELECT count(*)
FROM tbl_task
WHERE task_start_time < current_date
UNION ALL
SELECT count(*)
FROM tbl_task
WHERE task_start_time < date_sub(current_date, INTERVAL 1 DAY)
...
UNION ALL
SELECT count(*)
FROM tbl_task
WHERE task_start_time < date_sub(current_date, INTERVAL 9 DAY);
Edit:
You might also join a derived table that uses FROM-less SELECTs and UNION ALL to get the days to look back and then aggregate. This might be a little easier to construct dynamically. (But it may be slower I suspect.)
SELECT count(*)
FROM (SELECT 0 x
UNION ALL
SELECT 1
...
UNION ALL
SELECT 9)
INNER JOIN tbl_task t
ON t.task_start_time < date_sub(current_date, INTERVAL x.x DAY)
GROUP BY x.x;
In MySQL version 8+ you can even use a recursive CTE to construct the table with the days.
WITH RECURSIVE x
AS
(
SELECT 0 x
UNION ALL
SELECT x + 1
FROM x
WHERE x + 1 < 10
)
SELECT count(*)
FROM x
INNER JOIN tbl_task t
ON t.task_start_time < date_sub(current_date, INTERVAL x.x DAY)
GROUP BY x.x;
I am trying to find number of users every month.
This is my SQL which I learn from another question.
The part for creating number of month is easy to understand but it is long. I am wondering is there a neater way to write the same SQL. Thanks.
SELECT
meses.MONTH,
COUNT(Users.user_ID) AS num_of_user
FROM
(
SELECT
1 AS MONTH
UNION
SELECT
2 AS MONTH
UNION
SELECT
3 AS MONTH
UNION
SELECT
4 AS MONTH
UNION
SELECT
5 AS MONTH
UNION
SELECT
6 AS MONTH
UNION
SELECT
7 AS MONTH
UNION
SELECT
8 AS MONTH
UNION
SELECT
9 AS MONTH
UNION
SELECT
10 AS MONTH
UNION
SELECT
11 AS MONTH
UNION
SELECT
12 AS MONTH
) AS meses
LEFT JOIN
Users
ON
meses.month = MONTH(Users.joint_date) AND YEAR(Users.joint_date) = '2000'
GROUP BY
meses.MONTN
In MySQL 8.0, you can use a recursive query to generate the series.
I would also recommend filtering against literal dates rather than applying date function on the column being filtered: this is much more efficient, and can take advantage of an index on users(joint_date).
with dates as (
select '2020-01-01' dt
union all select dt + interval 1 month from dates where dt + interval 1 month < '2021-01-01'
)
select d.dt, count(u.user_id) as num_of_users
from dates d
left join users u
on u.joint_date >= d.dt
and u.joint_date < d.dt + interval 1 month
group by d.dt
In earlier versions, you do need to enumerate the dates, using union. However I would still recommend the literal date technique. That would look like:
select '2020-01-01' + interval n.n month as dt, count(u.user_id) as num_of_users
from (select 0 n union all select 2 ... union all select 11) n
left join users u
on u.joint_date >= '2020-01-01' + interval n.n month
and u.joint_date < '2020-01-01' + interval (n.n + 1) month
group by n.n
I have this query which outputs the count of rows for each day and if there are no rows, it outputs 0.
I now have an additional field I want to add into the query called 'Sender'. I need the query to do exactly the same but for each of the senders.
How can I perform a query so each Sender gets each day of the week with the values?
SELECT DAYNAME(DATE_SUB(CURDATE(), INTERVAL Days.n DAY)) AS `day`,
COUNT(r.List_Date) AS `total`
FROM (SELECT 1 as n UNION ALL SELECT 2 as n UNION ALL
SELECT 3 as n UNION ALL SELECT 4 as n UNION ALL
SELECT 5 as n UNION ALL SELECT 6 as n UNION ALL
SELECT 7 as n
) Days LEFT JOIN
returns r
ON r.List_Date >= DATE_SUB(CURDATE(), INTERVAL Days.n DAY)
GROUP BY Days.n
ORDER BY Days.n DESC
You need a cross join to get all the rows (each sender and each day of the week). Then use the left join:
SELECT s.sender, DAYNAME(DATE_SUB(CURDATE(), INTERVAL Days.n DAY)) AS `day`,
COUNT(r.List_Date) AS `total`
FROM (SELECT 1 as n UNION ALL SELECT 2 as n UNION ALL
SELECT 3 as n UNION ALL SELECT 4 as n UNION ALL
SELECT 5 as n UNION ALL SELECT 6 as n UNION ALL
SELECT 7 as n
) Days CROSS JOIN
(SELECT DISTINCT sender FROM returns) s LEFT JOIN
returns r
ON r.List_Date >= DATE_SUB(CURDATE(), INTERVAL Days.n DAY) and
r.sender = s.sender
GROUP BY s.sender, Days.n
ORDER BY s.sender, Days.n DESC;
This uses the returns table to get the appropriate senders. If you have another table, you can use that instead.
Although I have researched similar other questions, however could not reach the solution by following those, hence posting my following question, and apologies for a long question in an attempt to make my question more clear.
The image shows my table structure.
I want to run such a query to extract the 3 information,i.e
userId, count(), Date(viewTime)
i.e the no of counts of id that a user has viewed on daily basis in a interval of last 14 days,
also show count as 0 if there are no records for a user on a particular day
select userId, count(userId), Date(viewTime) from user_views
where DATE(viewTime) between DATE_SUB(DATE(NOW()), INTERVAL 90 DAY) AND now()
group by userId, date(viewTime);
By using the above query I am getting only the non-zero records, see in the following image:
However I want to show count as 0 for those days when there are no transaction of users. How do I achieve this?
You need to generate the dates dynamically for this and then use left join. Also note that since you are displaying the user_id it might be needed a cross join of distinct user_id with the dynamically generated dates.
From my previous answers related to showing missing dates MySql Single Table, Select last 7 days and include empty rows
Here is one for your case
select
t1.user_id,
coalesce(t2.cnt,0) as cnt,
t1.view_date
from
(
select DATE_FORMAT(a.Date,'%Y-%m-%d') as view_date,
x.user_id
from (
select curdate() - INTERVAL (a.a + (10 * b.a) + (100 * c.a)) DAY as Date
from (select 0 as a union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) as a
cross join (select 0 as a union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) as b
cross join (select 0 as a union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) as c
) a,(select distinct user_id from user_views)x
where a.Date between DATE_SUB(DATE(NOW()), INTERVAL 90 DAY) AND now()
)t1
left join
(
select user_id, count(user_id) as cnt, Date(view_time) as view_time from user_views
where DATE(view_time) between DATE_SUB(DATE(NOW()), INTERVAL 90 DAY) AND now()
group by user_id, date(view_time)
)t2
on t2.view_time = t1.view_date
and t1.user_id = t2.user_id
order by t1.view_date,t1.user_id
http://sqlfiddle.com/#!2/4136e/5
I have a query which returns the total of users who registered for each day. Problem is if a day had no one register it doesn't return any value, it just skips it. I would rather it returned zero
this is my query so far
SELECT count(*) total FROM users WHERE created_at < NOW() AND created_at >
DATE_SUB(NOW(), INTERVAL 7 DAY) AND owner_id = ? GROUP BY DAY(created_at)
ORDER BY created_at DESC
Edit
i grouped the data so i would get a count for each day- As for the date range, i wanted the total users registered for the previous seven days
A variation on the theme "build your on 7 day calendar inline":
SELECT D, count(created_at) AS total FROM
(SELECT DATE_SUB(NOW(), INTERVAL D DAY) AS D
FROM
(SELECT 0 as D
UNION SELECT 1
UNION SELECT 2
UNION SELECT 3
UNION SELECT 4
UNION SELECT 5
UNION SELECT 6
) AS D
) AS D
LEFT JOIN users ON date(created_at) = date(D)
WHERE owner_id = ? or owner_id is null
GROUP BY D
ORDER BY D DESC
I don't have your table structure at hand, so that would need adjustment probably. In the same order of idea, you will see I use NOW() as a reference date. But that's easily adjustable. Anyway that's the spirit...
See for a live demo http://sqlfiddle.com/#!2/ab5cf/11
If you had a table that held all of your days you could do a left join from there to your users table.
SELECT SUM(CASE WHEN U.Id IS NOT NULL THEN 1 ELSE 0 END)
FROM DimDate D
LEFT JOIN Users U ON CONVERT(DATE,U.Created_at) = D.DateValue
WHERE YourCriteria
GROUP BY YourGroupBy
The tricky bit is that you group by the date field in your data, which might have 'holes' in it, and thus miss records for that date.
A way to solve it is by filling a table with all dates for the past 10 and next 100 years or so, and to (outer)join that to your data. Then you will have one record for each day (or week or whatever) for sure.
I had to do this only for MS SqlServer, so how to fill a date table (or perhaps you can do it dynamically) is for someone else to answer.
A bit long winded, but I think this will work...
SELECT count(users.created_at) total FROM
(SELECT DATE_SUB(CURDATE(),INTERVAL 6 DAY) as cdate UNION ALL
SELECT DATE_SUB(CURDATE(),INTERVAL 5 DAY) UNION ALL
SELECT DATE_SUB(CURDATE(),INTERVAL 4 DAY) UNION ALL
SELECT DATE_SUB(CURDATE(),INTERVAL 3 DAY) UNION ALL
SELECT DATE_SUB(CURDATE(),INTERVAL 2 DAY) UNION ALL
SELECT DATE_SUB(CURDATE(),INTERVAL 1 DAY) UNION ALL
SELECT CURDATE()) t1 left join users
ON date(created_at)=t1.cdate
WHERE owner_id = ? or owner_id is null
GROUP BY t1.cdate
ORDER BY t1.cdate DESC
It differs from your query slightly in that it works on dates rather than date times which your query is doing. From your description I have assumed you mean to use whole days and therefore have used dates.