Result of a Query in One Column on Another Query - sql

Question

I need to create a report that shows attendance at a weekly class. We use an electronic check-in system so each person's info is saved with a date into the database.
I can easily write a query that gets the list of people who checked in to the class on a given day. The results from that query look something like this:
+-----------+------------+-----------+
| person id | first name | last name |
+-----------+------------+-----------+
| 1234 | john | smith |
| 1235 | jane | smith |
+-----------+------------+-----------+
But what I need is an additional column that says how many times the particular person has attended that class within a 12 week period. So the results I want would look something like this:
+-----------+------------+-----------+------------+
| person id | first name | last name | attendance |
+-----------+------------+-----------+------------+
| 1234 | john | smith | 3 |
| 1235 | jane | smith | 5 |
+-----------+------------+-----------+------------+
I can also get the proper results for the "attendance" column with a COUNT query. This query only works when I specify a person ID in the attendance table.
So I need a query that will take the person ids from the first query and figure out how many times that person has attended in the last 12 weeks and apply that to a column.
Additional information:
It needs to count how many times the person has attended that class in a 12 week period including the last Sunday.
It is always 12 weeks from the current date
I suppose it is possible they could have attended two classes in a day but all the classes are on a Sunday and it is unlikely enough that I do not need to account for this
It is all based on a Sunday so I guess the answer is 12 weeks from last Sunday.
Here's my query that returns the results of who checked in last Sunday:
SELECT
pb.person_id, pb.nick_name, pb.last_name, COS.occurrence_name, COS.occurrence_description, COS.date_created, COS.occurrence_type, COS.occurrence_id, sm.role_luid
FROM core_v_occurrence_service COS
JOIN core_occurrence_attendance oa ON oa.occurrence_id = COS.occurrence_id
JOIN core_v_person_basic pb ON pb.person_id = oa.person_id
JOIN smgp_member sm ON sm.person_id = OA.person_id
WHERE oa.attended = 1
AND COS.occurrence_type = 140
AND COS.date_created BETWEEN (DATEADD(week,-1,GETDATE())) AND GETDATE()
AND sm.role_luid IN (24,25, 28)
AND sm.group_id = 3
And here's the query that gives me the count of how many times someone has attended a class:
SELECT COUNT (oa.person_id)
FROM core_occurrence_attendance oa
JOIN core_v_occurrence_service COS on cos.occurrence_id = oa.occurrence_id
WHERE oa.person_id = 27276
AND oa.attended = 1
AND COS.occurrence_type = 140
AND COS.date_created BETWEEN (DATEADD(week,-12,GETDATE())) AND GETDATE()
Basically what I need is a query that count how many times a person's person id is entered into the attendance table. Because a person's person id will be entered into that table every time they attend the class.

Answer 1

You should be able to add a group by into the query:
SELECT Person_ID, FIRST_NAME, LAST_NAME, COUNT(Person_ID) AS Attendance
FROM <YOURTABLE>
WHERE <DateField> BETWEEN <begindate> AND <enddate>
GROUP BY Attendance
The group by will count how many times that person has shown up for class and put it into one cell.
I a not guaranteeing this code runs because you post is missing some information.replace everything in the angle brackets.

Answer 2

I did it!
I created a CTE for the query that counts the attendance.
I then did SELECT DISTINCT on that CTE and added a GROUP BY with all the column names.
I also added the date range of 12 weeks I needed in the CTE.