SQL group by school name - mysql

Question

school_name
class
medium
total
srk
1
english
13
srk
2
english
14
srk
3
english
15
srk
1
french
16
srk
2
french
16
srk
3
french
18
vrk
1
english
17
vrk
1
french
18
I want that output by
school_name
class1eng
class1french
class2eng
class2french
class3english
class3french
[output needed][ otput required
output

Answer 1

You’re looking for multiple select statements along with appropriate cases to satisfy.
This should work for you
Select
school_name,
Sum(Case when (class=1 and medium=‘English’) then total else 0 end) as class1english,
Sum(Case when (class=1 and medium=‘French’) then total else 0 end) as class1french,
Sum(Case when (class=2 and medium=‘English’) then total else 0 end) as class2english,
Sum(Case when (class=2 and medium=‘French’) then total else 0 end) as class2french,
Sum(Case when (class=3 and medium=‘English’) then total else 0 end) as class3english,
Sum(Case when (class=3 and medium=‘French’) then total else 0 end) as class3french
From
table_name
Group by
school_name

Answer 2

Seems to be a simple ask, assumed you also want to order your results. Please check below query if that helps
SELECT school_name, class, medium, SUM(total) AS Total
FROM <Table Name>
GROUP BY school_name, class, medium

Answer 3

This solution is for general purpose, complex, but functional.
I've made it for myself as exercise and challenge.
/* --------------- TABLE --------------- */
CREATE TABLE schools_tab
(school VARCHAR(9), class INT, subj VARCHAR(9), total INT);
INSERT INTO schools_tab VALUES
('srk', 1, 'english', 13),
('srk', 2, 'english', 14),
('srk', 3, 'english', 15),
('srk', 1, 'french', 16),
('srk', 2, 'french', 16),
('srk', 3, 'french', 18),
('vrk', 1, 'english', 17),
('vrk', 1, 'french', 18);
/* -------------- DYNAMIC QUERY --------------- */
SET #sql=NULL;
WITH cte AS (
SELECT school, class, subj, ROW_NUMBER() OVER (PARTITION BY school) AS idx, DENSE_RANK() OVER (ORDER BY school) AS ids
FROM (SELECT DISTINCT school FROM schools_tab) A LEFT JOIN (SELECT DISTINCT class, subj FROM schools_tab) B ON (1=1)
), cte2 AS (
SELECT A.ids, A.idx, A.school, A.class, A.subj, COALESCE(B.total, 0) AS total
FROM cte A LEFT JOIN schools_tab B ON (A.school=B.school AND A.class=B.class AND A.subj=B.subj)
), cte3 AS (
SELECT DISTINCT class, subj
FROM schools_tab
ORDER BY class, subject
)
SELECT CONCAT('WITH RECURSIVE cte AS (
SELECT school, class, subj, ROW_NUMBER() OVER (PARTITION BY school) AS idx, DENSE_RANK() OVER (ORDER BY school) AS ids
FROM (SELECT DISTINCT school FROM schools_tab) A LEFT JOIN (SELECT DISTINCT class, subj FROM schools_tab) B ON (1=1)
), cte2 AS (
SELECT A.ids, A.idx, A.school, A.class, A.subj, COALESCE(B.total, 0) AS total
FROM cte A LEFT JOIN schools_tab B ON (A.school=B.school AND A.class=B.class AND A.subj=B.subj)
), ctx AS ('
'SELECT (SELECT MAX(ids) FROM cte2) AS n,',
GROUP_CONCAT(DISTINCT CONCAT( '(SELECT total FROM cte2 WHERE idx=',idx,' AND ids=n) AS class',class,subj ) ORDER BY class, subj),
' UNION ALL SELECT n-1 AS n,',
GROUP_CONCAT(DISTINCT CONCAT( '(SELECT total FROM cte2 WHERE idx=',idx,' AND ids=n) AS class',class,subj ) ORDER BY class, subj),
' FROM ctx WHERE n>0',
') SELECT DISTINCT SUBSTRING_INDEX(SUBSTRING_INDEX(''srk,vrk'', '','', n+1), '','', -1) AS school,',
GROUP_CONCAT(DISTINCT CONCAT('class',class,subj)),
' FROM ctx ORDER BY school'
) INTO #sql
FROM cte2;
PREPARE stmt1 FROM #sql;
EXECUTE stmt1;