I'm new to SQL and am a bit confused on how I would write a query in order to get the count of state in a different table.
Ie i have this table [student]
id
school_code
0
0123
1
2345
2
2345
And this other table [school]
school_code
name
State
0123
xxyy
New Jersey
2345
xyxy
Washington
3456
yxyx
Colarado
I want to find out how I would get this table which tells me the entries for state by checking each student and making a count of how often that state occurs, ordered by most occurrences in student table.
State
No. times occured (iterating through student)
Washington
2
New Jersey
1
SELECT school.state, count(school.state)
FROM student, school
WHERE student.school_code = school.school_code
GROUP BY school.state
ORDER BY count(school.state)`
I'm not sure whether this would be iterating through each student and counting them?
Or just natural-joinging student and school and then counting all the states
When I run this on data supplied, the numbers of times occurred is a really low number which doesn't seem right?
We can simply JOIN the two tables and COUNT the school code in the students table, with GROUP BY state:
SELECT
sc.state, COUNT(st.school_code)
FROM
school sc
JOIN student st
ON sc.school_code = st.school_code
GROUP BY sc.state;
We can try out here: db<>fiddle
Related
This has been driving me and my team up the wall. I cannot compose a query that will strict match a single record that has a specific permutation of look ups.
We have a single lookup table
room_member_lookup:
room | member
---------------
A | Michael
A | Josh
A | Kyle
B | Kyle
B | Monica
C | Michael
I need to match a room with an exact list of members but everything else I've tried on stack overflow will still match room A even if I ask for a room with ONLY Josh and Kyle
I've tried queries like
SELECT room FROM room_member_lookup
WHERE member IN (Josh, Michael)
GROUP BY room
HAVING COUNT(1) = 2
However this will still return room A even though that has 3 members I need a exact member permutation and that matches the room even not partials.
SELECT room
FROM room_member_lookup a
WHERE member IN ('Monica', 'Kyle')
-- Make sure that the room 'a' has exactly two members
and (select count(*)
from room_member_lookup b
where a.room=b.room)=2
GROUP BY room
-- and both members are in that room
HAVING COUNT(1) = 2
Depending on the SQL dialect, one can build a dynamic table (CTE or select .. union all) to hold the member set (Monica and Kyle, for example), and then look for set equivalence using MINUS/EXCEPT sql operators.
I have two tables
TicketsForSale
ticket_id (PK)
type
category
Transactions
transaction_id (PK)
ticket_id (FK)
I want to get the transactions per type of tickets. This is what I've tried:
SELECT ticketsforsale.type
, COUNT(transactions.ticket_id)
FROM ticketsforsale
INNER JOIN transactions ON ticketsforsale.ticket_id = transactions.ticket_id
GROUP BY ticketsforsale.type
What I hope for as a result is something like this
{
Sports 5
Theater 7
Cruise 8
Cinema 10
}
But instead I get the following :
{ Theater 2
Cruise 1
Sports 1
Sports 2
Cruise 3
Cinema 5
}
The numbers aren't accurate, just used for demonstration.
(The category column is listing the specific show you attend by "purchasing" the ticket. E.G If the type is "Sports", the category could be Basketball or Football or Volleyball etc. etc. ) I just thought that this column could somehow be the issue here, but maybe I'm wrong.
Try this:
select distinct type
, encode(type::bytea,'hex') hex_type
from TicketsForSale order by 1;
You'll probably find that you have multiple type values that appear identical but have different hexadecimal representations. Fix those discrepancies, and the you should be good to go.
I'm trying to count the Total Number of Supervisors for each branch according to branch ID (B001, B002, B003). I'm trying to get the result like 'Sandy' counted as 1 and 'Mandy' counted as another (total 2 supervisors for B001) but after i executed, the result showed 3 (Sandy counted separately as 2 different values instead of 1). so, what should i do to make total number of supervisor in B001 branch becomes 2.
there are 3 B001 in that table, but the supervisors are only sandy and mandy which Supervisor Sandy is repeated. The result showed there are 3 supervisors after i executed, so how can i make it to 2?)
results shown:
2
SELECT Staff.BranchID,Branch.Manager AS ManagerName,
COUNT (staff.Supervisor) AS TotalNumberofSupervisor
FROM Staff INNER JOIN Branch ON Branch.BranchID = Staff.BranchID
GROUP BY Staff.BranchID,Branch.Manager
I think "COUNT (distinct(staff.Supervisor))" instead of
"COUNT (staff.Supervisor)" will help
At the moment I am busy with two tables, Students and Classes. These two both contain a column project_group, a way to categorize multiple students from one class into smaller groups.
In the Students table there is a column City that states in which town/city students live, from the rows that have been filled there are already several cities occurring multiple times. The code I used to check how many times a city is being showed is this:
SELECT City, count(*)
FROM Students
GROUP BY City
Now the next thing I want to do is show per class in which cities the students live and how many live there, so for example a result like:
A | - | 2
A | New York | 3
A | Los Angeles | 1
B | - | 1
B | Miami | 2
B | Seattle | 1
Students and Classes can join each other on the column project_group but what I'm mostly interested in his using both the GROUP BY mentioned earlier, using the JOIN and also showing the results per class.
Thanks in advance,
KRAD
I'm not sure what the column name is for A and B in your example. I'm assuming Classes.Class in the following:
SELECT
C.Class
, S.City
, COUNT(S.*) AS Count
FROM
Classes AS C INNER JOIN
Students AS S ON C.Project_Group = S.Project_Group
GROUP BY
C.Class
, S.City
I managed to get it working. While doing some tests to see which exact error message it was that I got, I used this and managed to get it working. I now get an overview per class that shows how many people live in which city. This is the code used.
SELECT class_id, city, count(*) AS amount
FROM students, classes
WHERE students.project_group = classes.project_group
GROUP BY class_id, city
ORDER BY class_id
Struggling getting a query to work……..
I have two tables:-
tbl.candidates:
candidate_id
agency_business_unit_id
tbl.candidate_employment_tracker
candidate_id
The candidate employment can have duplicate records of a candidate_id as it contains records on their working history for different clients.
The candidates tables is unique for each candidate.
I'm trying to obtain results which will group by agency_business_unit_id and count the amount of candidates each has which exist in the candidate_employment_tracker.
E.g.
Agency Business Unit Id | Candidates
------------------------------------------------------------
100 | 2
987 | 1
12 | 90
The query I'm working on doesn't appear to be working as I'm getting the count of the candidates in candidate_employment_tracker.
SELECT
abu.agency_business_unit_id,
abu.agency_business_unit_name,
count(c.candidate_id) AS candidateCount
FROM candidate_employment_tracker cet
INNER JOIN candidate c ON c.candidate_id = cet.candidate_id
INNER JOIN agency_business_unit abu ON abu.agency_business_unit_id = c.agency_business_unit_id
WHERE c.candidate_ni_number NOT REGEXP '^[A-CEGHJ-PR-TW-Z][A-CEGHJ-NPR-TW-Z] ?[0-9]{2} ?[0-9]{2} ?[0-9]{2} ?[ABCD]$'
GROUP BY abu.agency_business_unit_id
ORDER BY abu.agency_business_unit_name ASC
I've tried several approaches and the results are inconsistent. For instance I know one of the agency business units only has 1 candidate but the result is 2. This is as a result of this particular candidate having 2 records in the candidate employment tracker table. I'll keep bashing away but any help would be much appreciated.
Do you need
count(DISTINCT c.candidate_id)
That would avoid the double counting where candidates have 2 records in the candidate employment tracker table.
Hmmm this doesn't appear to work now that I look further into the results. When I compare the candidates for a agency business unit I get inconsistent count numbers.