I have the below query which comes from this post count number of items in a row in mysql which counts how many times in a row a student has been present/absent from a class.
SELECT
classlist.studentid,
student.name,
classStatus.name status,
COUNT(*) presentcnt
FROM
classlist
INNER JOIN student ON classlist.studentid=student.id
INNER JOIN classstatus ON classlist.presentid=classstatus.id
INNER JOIN (
SELECT
studentid,
max(CASE WHEN presentid=0 THEN id END) max_0,
max(CASE WHEN presentid=1 THEN id END) max_1
FROM classlist
GROUP BY studentid
) s
ON coalesce(classlist.id>least(max_0,max_1) AND classlist.id<=greatest(max_0,max_1),1) AND s.studentid=classlist.studentid
GROUP BY classlist.studentid
This works as expected,
STUDENTID NAME STATUS PRESENTCNT
111 John Present 1
222 Kate Absent 2
333 Matt Present 5
I want to extend the query so that I have a column showing if the student particpated in the class.
If I run an independent query I get the results I want
SELECT
classlist.studentid,
student.name,
participatedStatus.name status,
COUNT(*) participatedcnt
FROM
classlist
INNER JOIN student ON classlist.studentid=student.id
INNER JOIN participatedStatus ON classlist.participatedid=participatedStatus.id
INNER JOIN (
SELECT
studentid,
max(CASE WHEN participatedid=0 THEN id END) max_0,
max(CASE WHEN participatedid=1 THEN id END) max_1
FROM classlist
group by studentid
) s
ON coalesce(classlist.id>least(max_0,max_1)
AND classlist.id<=greatest(max_0,max_1),1)
AND s.studentid=classlist.studentid
group by classlist.studentid
STUDENTID NAME STATUS PARTICIPATEDCNT
111 John Yes 1
222 Kate No 2
333 Matt Yes 2
However I want to merge them into the one query so I get
STUDENTID NAME STATUS PRESENTCNT STATUS2 PARTICIPATEDCNT
111 John Present 1 Yes 1
222 Kate Absent 2 No 2
333 Matt Present 5 Yes 2
I am confused about how this can be achieved as I am selecting count *, how can I acheive this?
A sample of the data I am using is in this fiddle and below
CREATE TABLE classlist
(`id` int, `studentid` int, `subjectid` int, `presentid` int, `participatedid` int);
CREATE TABLE student
(`id` int, `name` varchar(4));
CREATE TABLE subject
(`id` int, `name` varchar(4));
CREATE TABLE classStatus
(`id` int, `name` varchar(8));
CREATE TABLE participatedStatus
(`id` int, `name` varchar(8));
INSERT INTO classlist (`id`, `studentid`, `subjectid`, `presentid`, `participatedid`)
VALUES (1, 111, 1, 1, 0), (2, 222, 3, 0, 0), (3, 333, 2, 1, 0), (4, 111, 4, 0, 0), (5, 111, 1, 1, 0), (6, 222, 3, 0, 0), (7, 333, 2, 1, 1), (8, 111, 4, 0, 0), (9, 111, 4, 0, 0), (10, 111, 4, 0, 0), (11, 111, 1, 1, 1), (12, 333, 3, 1, 0), (13, 333, 2, 1, 1), (14, 333, 3, 1, 1);
INSERT INTO student (`id`, `name`)
VALUES (111, 'John'),(222, 'Kate'),(333, 'Matt');
INSERT INTO subject (`id`, `name`)
VALUES (1, 'MATH'),(2, 'ENG'),(3, 'SCI'),(4, 'GEO');
INSERT INTO classStatus (`id`, `name`)
VALUES (0, 'Absent'), (1, 'Present');
INSERT INTO participatedStatus (`id`, `name`)
VALUES (0, 'No'),(1, 'Yes');
SELECT
studid,
studname,
status,
presentcnt,
status1,
participatedcnt FROM
(SELECT
classlist.studentid studid,
student.name studname,
classStatus.name status,
COUNT(*) presentcnt
FROM
classlist
INNER JOIN student ON classlist.studentid=student.id
INNER JOIN classstatus ON classlist.presentid=classstatus.id
INNER JOIN (
SELECT
studentid,
max(CASE WHEN presentid=0 THEN id END) max_0,
max(CASE WHEN presentid=1 THEN id END) max_1
FROM classlist
GROUP BY studentid
) s
ON coalesce(classlist.id>least(max_0,max_1) AND classlist.id<=greatest(max_0,max_1),1) AND s.studentid=classlist.studentid
GROUP BY classlist.studentid)x
JOIN
(SELECT
classlist.studentid,
student.name,
participatedStatus.name status1,
COUNT(*) participatedcnt
FROM
classlist
INNER JOIN student ON classlist.studentid=student.id
INNER JOIN participatedStatus ON classlist.participatedid=participatedStatus.id
INNER JOIN (
SELECT
studentid,
max(CASE WHEN participatedid=0 THEN id END) max_0,
max(CASE WHEN participatedid=1 THEN id END) max_1
FROM classlist
group by studentid
) s
ON coalesce(classlist.id>least(max_0,max_1)
AND classlist.id<=greatest(max_0,max_1),1)
AND s.studentid=classlist.studentid
group by classlist.studentid)y
ON x.studid=y.studentid
Fiddle
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