The following code returns a couple of numbers, identifying people who take part in more than three activities.
SELECT pnr
FROM Participates
GROUP BY pnr
HAVING count(activities)>3;
I want the answer to be the number of people who participate in more than three activities though, i.e. "4", instead of four unique numbers. What to do?
Access supports derived tables.
SELECT COUNT(*) AS NumberOfParticipants FROM
(
SELECT pnr
FROM Participates
GROUP BY pnr
HAVING count(activities)>3
) T
You will need a WHERE clause on the pnr field to uniquely identify one of your groupings:
SELECT COUNT(pnr)
FROM Participates
GROUP BY pnr
WHERE pnr = 'whatever'
HAVING COUNT(activities)>3
The order of my clauses might be wrong
Select Count(Distinct pnr)
From Participates
Having Count(activities) > 3
Related
I'm trying to use a common table expression to find the differences between two queries I wrote. The first query returns how many patients belong to each ROOMID(each ID represent a specific room).
Second query I have is how many patients that belong to each ROOMId have surgery operated on them. PatientID represent each patient.
select roomID, count(distinct patientID) as totalinsurgery
from data with (nolock)
where ptprocess = 'surgery'
group by clientid, batchid
Second query:
select CAroomid, sum(patientsinroom) as patientsinroom
from data
group by caroomid
So the idea behind is try to get the 'difference' in result of the two query. So how many patients in the room went to surgery. What is the best way to use common table expression to get the result?
So how many patients in the room went to surgery.
I suspect you just want conditional aggregation:
select roomId,
count(distinct case when ptprocess = 'surgery' then patientID end) as num_surgery
count(distinct patientID) as total
from data
group by roomId;
Note: I have no idea why you are using count(distinct). Can a patient really occur more than one time in a room?
I think this is very easy, I was hoping for verification.
I have 2 columns: ID & DocumentNumber. It's a one-to-many relationship, one ID can have many document numbers.
I need to get ID's where all DocumentNumbers belonging to it are unique.
Is this what Group By is for, in conjunction with Distinct? Is it as simple as Grouping By the ID
You can (as you're suspecting) do it using a simple GROUP BY/HAVING and using DISTINCT;
SELECT id FROM documents
GROUP BY id
HAVING COUNT(DocumentNumber) = COUNT(DISTINCT DocumentNumber)
An SQLfiddle to test with.
I've just created this query and I get confuse by the time I grouping this because I can't see them as one grouping. This query runs but not the way I wanted, I want to group the query by the team name but the problem occurs when its query being counted using count(*) and the result of its counting produces the same number ,,,
SELECT TEAM.NAMATEAM, PERSONAL.KODEPERSON
FROM TEAM, PERSONAL
WHERE TEAM.KODETEAM = PERSONAL.KODETEAM
GROUP BY PERSONAL.KODEPERSON, TEAM.NAMATEAM
MINUS
SELECT TEAM.NAMATEAM, PERSONAL.KODEPERSON
FROM TEAM, PERSONAL, AWARD_PERSON
WHERE TEAM.KODETEAM = PERSONAL.KODETEAM
AND AWARD_PERSON.PEMENANG = PERSONAL.KODEPERSON
GROUP BY TEAM.NAMATEAM, PERSONAL.KODEPERSON;
I want to group all these using the team name but using counting will be problem since I have no idea to group within the technique that can be run smoothly as I wanted. Thank you.
Do I understand your question? You are trying to make a table of columns NAMATEAM,X where NAMATEAM are the team names, and X are the number of people on each team who do not have awards (listed in AWARD_PERSON). If so, you should be able to use a sub-select:
SELECT T_NAME, COUNT(*)
FROM (
SELECT TEAM.NAMATEAM "T_NAME", PERSONAL.KODEPERSON
FROM TEAM, PERSONAL
WHERE TEAM.KODETEAM = PERSONAL.KODETEAM
MINUS
SELECT TEAM.NAMATEAM "T_NAME", PERSONAL.KODEPERSON
FROM TEAM, PERSONAL, AWARD_PERSON
WHERE TEAM.KODETEAM = PERSONAL.KODETEAM
AND AWARD_PERSON.PEMENANG = PERSONAL.KODEPERSON )
-- your original query without the GROUP BYs
GROUP BY T_NAME
The first subselect SELECT creates a full list of players, the second subselect SELECT creates a list of players who have won awards (I assume), the MINUS removes the award winners from the full list. Thus the full subselect returns a list of players and their teams, for all players without awards.
The main SELECT then summarizes on the team name only, to yield a per-team count of players without awards.
You should not need your original GROUP BY TEAM.NAMATEAM, PERSONAL.KODEPERSON, unless you have duplicate rows in your database, e.g., one player on one team has more than one row in the database.
I'm struggling to understand what this query is doing:
SELECT branch_name, count(distinct customer_name)
FROM depositor, account
WHERE depositor.account_number = account.account_number
GROUP BY branch_name
What's the need of GROUP BY?
You must use GROUP BY in order to use an aggregate function like COUNT in this manner (using an aggregate function to aggregate data corresponding to one or more values within the table).
The query essentially selects distinct branch_names using that column as the grouping column, then within the group it counts the distinct customer_names.
You couldn't use COUNT to get the number of distinct customer_names per branch_name without the GROUP BY clause (at least not with a simple query specification - you can use other means, joins, subqueries etc...).
It's giving you the total distinct customers for each branch; GROUP BY is used for grouping COUNT function.
It could be written also as:
SELECT branch_name, count(distinct customer_name)
FROM depositor INNER JOIN account
ON depositor.account_number = account.account_number
GROUP BY branch_name
Let's take a step away from SQL for a moment at look at the relational trainging language Tutorial D.
Because the two relations (tables) are joined on the common attribute (column) name account_number, we can use a natural join:
depositor JOIN account
(Because the result is a relation, which by definition has only distinct tuples (rows), we don't need a DISTINCT keyword.)
Now we just need to aggregate using SUMMARIZE..BY:
SUMMARIZE (depositor JOIN account)
BY { branch_name }
ADD ( COUNT ( customer_name ) AS customer_tally )
Back in SQLland, the GROUP BY branch_name is doing the same as SUMMARIZE..BY { branch_name }. Because SQL has a very rigid structure, the branch_name column must be repeated in the SELECT clause.
If you want to COUNT something (see SELECT-Part of the statement), you have to use GROUP BY in order to tell the query what to aggregate. The GROUP BY statement is used in conjunction with the aggregate functions to group the result-set by one or more columns.
Neglecting it will lead to SQL errors in most RDBMS, or senseless results in others.
Useful link:
http://www.w3schools.com/sql/sql_groupby.asp
I have a table with several "ticket" records in it. Each ticket is stored by day (i.e. 2011-07-30 00:00:00.000) I would like to count the unique records in each month by year I have used the following sql statement
SELECT DISTINCT
YEAR(TICKETDATE) as TICKETYEAR,
MONTH(TICKETDATE) AS TICKETMONTH,
COUNT(DISTINCT TICKETID) AS DAILYTICKETCOUNT
FROM
NAT_JOBLINE
GROUP BY
YEAR(TICKETDATE),
MONTH(TICKETDATE)
ORDER BY
YEAR(TICKETDATE),
MONTH(TICKETDATE)
This does produce a count but it is wrong as it picks up the unique tickets for every day. I just want a unique count by month.
Try combining Year and Month into one field, and grouping on that new field.
You may have to cast them to varchar to ensure that they don't simply get added together. Or.. you could multiple through the year...
SELECT
(YEAR(TICKETDATE) * 100) + MONTH(TICKETDATE),
count(*) AS DAILYTICKETCOUNT
FROM NAT_JOBLINE GROUP BY
(YEAR(TICKETDATE) * 100) + MONTH(TICKETDATE)
Presuming that TICKETID is not a primary or unique key, but does appear multiple times in table NAT_JOBLINE, that query should work. If it is unique (does not occur in more than 1 row per value), you will need to select on a different column, one that uniquely identifies the "entity" that you want to count, if not each occurance/instance/reference of that entity.
(As ever, it is hard to tell without working with the actual data.)
I think you need to remove the first distinct. You already have the group by. If I was the first Distict I would be confused as to what I was supposed to do.
SELECT
YEAR(TICKETDATE) as TICKETYEAR,
MONTH(TICKETDATE) AS TICKETMONTH,
COUNT(DISTINCT TICKETID) AS DAILYTICKETCOUNT
FROM NAT_JOBLINE
GROUP BY YEAR(TICKETDATE), MONTH(TICKETDATE)
ORDER BY YEAR(TICKETDATE), MONTH(TICKETDATE)
From what I understand from your comments to Phillip Kelley's solution:
SELECT TICKETDATE, COUNT(*) AS DAILYTICKETCOUNT
FROM NAT_JOBLINE
GROUP BY TICKETDATE
should do the trick, but I suggest you update your question.