I have a table like the following
User Item
A 1
A 1
A 1
B 1
B 2
C 2
C 2
A 2
I'm trying to run a query so I can get an output such as
User Item Count
A 1 3
B 1 1
B 2 1
A 2 1
C 2 2
I've tried the following query, however I'm not getting the output right.
select f.item,f.uid, COUNT(f.uid) as count
from fresh f,
product p
where f.locationid = p.iid
group by f.locationid, f.uid
order by f.uid desc;
Can anyone point out how I write a query to get the required output? I could write it up in python / ruby but I think it'll take a lot longer to run! :(
Select user, Item, count(*) Count From tablename
Group by User, Item
Order by Item
SELECT user, item, count(*) FROM fresh GROUP BY user, item
Why are you joining to the product table, when it is not used in the results?
That is likely cause of the issue, since it is an inner join, when there isn't a match, there will be no result, so you'll lose data, try just:
select
item,
uid,
COUNT(*) as count
from
fresh
group by
locationid,
uid
order by
uid desc
;
Related
I work in healthcare. In a Postgres database, we have a table member IDs and dates. I'm trying to pull the latest two dates for each member ID.
Simplified sample data:
A 1
B 1
B 2
C 1
C 5
C 7
D 1
D 2
D 3
D 4
Desired result:
A 1
B 1
B 2
C 1
C 5
D 1
D 2
I get a strong feeling this is for a homework assignment and would recommend that you look into partitioning and specifically rank() function by yourself first before looking at my solution.
Moreover, you have not specified how you received the initial result you provided, so I'll have to assume you just did select letter_column, number_column from my_table; to achieve the result.
So, what you actually want here is partition the initial query result into groups by the letter_column and select the first two rows in each. rank() function lets you assign each row a number, counting within groups:
select letter_column,
number_column,
rank() over (partition by letter_column order by number_column) as rank
from my_table;
Since it's a function, you can't use it in a predicate in the same query, so you'll have to build another query around this one, this time filtering the results where rank is over 2:
with ranked_results as (select letter_column,
number_column,
rank() over (partition by letter_column order by number_column asc) as rank
from my_table mt)
select letter_column,
number_column
from ranked_results
where rank < 3;
Here's an SQLFiddle to play around: http://sqlfiddle.com/#!15/e90744/1/0
Hope this helps!
I have two tables - StepModels (support plan) and FeedbackStepModels (feedback), StepModels keeps how many steps each support plan requires.
SELECT [SupportPlanID],COUNT(*)AS Steps
FROM [StepModels]
GROUP BY SupportPlanID
SupportPlanID (Steps)
-------------------------------
1 4
2 9
3 3
4 10
FeedbackStepModels keeps how many steps employee entered the system
SELECT [FeedbackID],SupportPlanID,Count(*)AS StepsNumber
FROM [FeedbackStepModels]
GROUP BY FeedbackID,SupportPlanID
FeedbackID SupportPlanID
---------------------------------------------
1 1 3 --> this suppose to be 4
2 2 9 --> Correct
3 3 0 --> this suppose to be 3
4 4 10 --> Correct
If submitted Feedback steps total is less then required total amount I want to delete this wrong entry from the database. Basically i need to delete FeedbackID 1 and 3.
I can load the data into List and compare and delete it, but want to know if we can we do this in SQL rather than C# code.
You can use the query below to remove your unwanted data by SQL Script
DELETE f
FROM FeedbackStepModels f
INNER JOIN (
SELECT [FeedbackID],SupportPlanID, Count(*) AS StepsNumber
FROM [FeedbackStepModels]
GROUP BY FeedbackID,SupportPlanID
) f_derived on f_derived_FeedbackID=f.FeedBackID and f_derived.SupportPlanID = f.SupportPlanID
INNER JOIN (
SELECT [SupportPlanID],COUNT(*)AS Steps
FROM [StepModels]
GROUP BY SupportPlanID
) s_derived on s_derived.SupportPlanID = f.SupportPlanID
WHERE f_derived.StepsNumber < s_derived.Steps
I think you want something like this.
DELETE FROM [FeedbackStepModels]
WHERE FeedbackID IN
(
SELECT a.FeedbackID
FROM
(
SELECT [FeedbackID],
SupportPlanID,
COUNT(*) AS StepsNumber
FROM [FeedbackStepModels]
GROUP BY FeedbackID,
SupportPlanID
) AS a
INNER JOIN
(
SELECT [SupportPlanID],
COUNT(*) AS Steps
FROM [StepModels]
GROUP BY SupportPlanID
) AS b ON a.SupportPlanID = b.[SupportPlanID]
WHERE a.StepsNumber < b.Steps
);
Imagine I have a table like this:
# | A | B | MoreFieldsHere
1 1 1
2 1 3
3 1 5
4 2 6
5 2 7
6 3 9
B is associated to A in an 1:n relationship. The table could've been created with a join for example.
I want to get both the total count and the count of different A.
I know I can use a query like this:
SELECT v1.cnt AS total, v2.cnt AS num_of_A
FROM
(
SELECT COUNT(*) AS cnt
FROM SomeComplicatedQuery
WHERE 1=1
-- AND SomeComplicatedCondition
) v1,
(
SELECT COUNT(A) AS cnt
FROM SomeComplicatedQuery
WHERE 1=1
-- AND SomeComplicatedCondition
GROUP BY A
) v2
However SomeComplicatedQuery would be a complicated and slow query and SomeComplicatedCondition would be the same in both cases. And I want to avoid calling it unnessesarily. Aside from that if the query changes, you need to make sure to change it in the other place too, making it prone to error and creating (probably unnessesary) work.
Is there a way to do this more efficiently?
Are you looking for this?
SELECT COUNT(*) AS total, COUNT(DISTINCT A) AS num_of_A
FROM (. . . ) q
I am still new to this Access and am not sure how to do this. I have this prospective customer table:
my table and the expected result:
Or here is the data, not sure if it will show correctly:
ID Dates Status
1 12-Sep-15 Follow up
1 2-Jan-15 Request
1 15-Apr-14 Letter
2 1-Sep-15 Request
2 1-Apr-15 Letter
3 12-Dec-15 Follow up
3 11-Sep-14 Request
3 12-Mar-14 Letter
4 14-Jan-16 Letter
4 12-Dec-15 Email
5 12-Jan-16 Letter
5 1 Des 2015 Email
And the result would be like this:
Follow up 2
Request 1
Letter 2
I first tried this SQL:
SELECT id, status, Max(dates) AS TEST
FROM Sample
GROUP BY id, status;
which still would give me the original table. I was hoping it would return the id and status for most recent dates.
Any help would be deeply appreciated. Thank you very much !!
If you want id and status for the latest date, then you need to use a subselect to get the max dates by id and join your table on it by id and date:
SELECT s.id, s.status, t.maxdate
FROM status as s
INNER JOIN
(SELECT id, Max(dates) AS maxdate
FROM Sample
GROUP BY id) as t ON t.id=s.id and t.maxdate=s.dates
database table like this
============================
= suburb_id | value
= 1 | 2
= 1 | 3
= 2 | 4
= 3 | 5
query is
SELECT COUNT(suburb_id) AS total, suburb_id
FROM suburbs
where suburb_id IN (1,2,3,4)
GROUP BY suburb_id
however, while I run this query, it doesn't give COUNT(suburb_id) = 0 when suburb_id = 0
because in suburbs table, there is no suburb_id 4, I want this query to return 0 for suburb_id = 4, like
============================
= total | suburb_id
= 2 | 1
= 1 | 2
= 1 | 3
= 0 | 4
A GROUP BY needs rows to work with, so if you have no rows for a certain category, you are not going to get the count. Think of the where clause as limiting down the source rows before they are grouped together. The where clause is not providing a list of categories to group by.
What you could do is write a query to select the categories (suburbs) then do the count in a subquery. (I'm not sure what MySQL's support for this is like)
Something like:
SELECT
s.suburb_id,
(select count(*) from suburb_data d where d.suburb_id = s.suburb_id) as total
FROM
suburb_table s
WHERE
s.suburb_id in (1,2,3,4)
(MSSQL, apologies)
This:
SELECT id, COUNT(suburb_id)
FROM (
SELECT 1 AS id
UNION ALL
SELECT 2 AS id
UNION ALL
SELECT 3 AS id
UNION ALL
SELECT 4 AS id
) ids
LEFT JOIN
suburbs s
ON s.suburb_id = ids.id
GROUP BY
id
or this:
SELECT id,
(
SELECT COUNT(*)
FROM suburb
WHERE suburb_id = id
)
FROM (
SELECT 1 AS id
UNION ALL
SELECT 2 AS id
UNION ALL
SELECT 3 AS id
UNION ALL
SELECT 4 AS id
) ids
This article compares performance of the two approaches:
Aggregates: subqueries vs. GROUP BY
, though it does not matter much in your case, as you are querying only 4 records.
Query:
select case
when total is null then 0
else total
end as total_with_zeroes,
suburb_id
from (SELECT COUNT(suburb_id) AS total, suburb_id
FROM suburbs
where suburb_id IN (1,2,3,4)
GROUP BY suburb_id) as dt
#geofftnz's solution works great if all conditions are simple like in this case. But I just had to solve a similar problem to generate a report where each column in the report is a different query. When you need to combine results from several select statements, then something like this might work.
You may have to programmatically create this query. Using left joins allows the query to return rows even if there are no matches to suburb_id with a given id. If your db supports it (which most do), you can use IFNULL to replace null with 0:
select IFNULL(a.count,0), IFNULL(b.count,0), IFNULL(c.count,0), IFNULL(d.count,0)
from (select count(suburb_id) as count from suburbs where id=1 group by suburb_id) a,
left join (select count(suburb_id) as count from suburbs where id=2 group by suburb_id) b on a.suburb_id=b.suburb_id
left join (select count(suburb_id) as count from suburbs where id=3 group by suburb_id) c on a.suburb_id=c.suburb_id
left join (select count(suburb_id) as count from suburbs where id=4 group by suburb_id) d on a.suburb_id=d.suburb_id;
The nice thing about this is that (if needed) each "left join" can use slightly different (possibly fairly complex) query.
Disclaimer: for large data sets, this type of query might have not perform very well (I don't write enough sql to know without investigating further), but at least it should give useful results ;-)