Reputation: 484
I'm trying to generate a pivot view from three tables:
The tables:
Students Table
+----+-----------+-----------+----------------+----------------+-------+
| id | school_id | last_name | first_name | middle_initial | yrlvl |
+----+-----------+-----------+----------------+----------------+-------+
| 1 | 2080295 | Doe | John | A | 3 |
| 2 | 0239129 | Rizal | Jose | M | 4 |
| 3 | 1231238 | Santos | Jane | M | 2 |
+----+-----------+-----------+----------------+----------------+-------+
Fee table
+----+--------------------+------------+
| id | fee_name | fee_amount |
+----+--------------------+------------+
| 1 | Registration Fee | 100 |
| 2 | News Letter | 100 |
| 3 | T-Shirt | 250 |
| 4 | Party | 500 |
+----+--------------------+------------+
stud_fee table
+----+------------+-----+
| id | stud_id | fee_id |
+----+---------+--------+
| 1 | 1 | 1 |
| 2 | 1 | 2 |
| 3 | 1 | 3 |
| 4 | 2 | 1 |
| 5 | 3 | 1 |
| 6 | 3 | 4 |
+----+---------+--------+
I would like to make the fee as the columns and students as the rows. I would like to make it display as:
+-----------+------------------+-------------+---------+-------+-------+
| school_id | Registration Fee | News Letter | T-Shirt | Party | Total |
+-----------+------------------+-------------+---------+-------+-------+
| 2080295 | 100 | 100 | 250 | | 450 |
| 0239129 | 100 | | | | 100 |
| 1231238 | 100 | | | 500 | 600 |
+-----------+------------------+-------------+---------+-------+-------+
Upvotes: 2
Views: 330
Reputation: 247720
It looks like you might have an unknown number of fees that you want to turn into columns, if that is the case then you will want to use prepared statements to query this:
SET @sql = NULL;
SELECT
GROUP_CONCAT(DISTINCT
CONCAT(
'max(case when f.fee_name = ''',
f.fee_name,
''' then f.fee_amount else 0 end) AS `',
f.fee_name, '`'
)
) INTO @sql
FROM fee f;
SET @sql = CONCAT('SELECT s.school_id, ', @sql, '
, sum(f.fee_amount) as Total
FROM students s
LEFT JOIN stud_fee sf
on s.id = sf.stud_id
LEFT JOIN fee f
on sf.fee_id = f.id
GROUP BY s.school_id');
PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
Upvotes: 4
Reputation: 79939
Try this:
SELECT
s.school_id,
MAX(CASE WHEN f.fee_name = 'Registration Fee' THEN f.fee_amount END)
AS 'Registration Fee',
MAX(CASE WHEN f.fee_name = 'News Letter' THEN f.fee_amount END)
AS 'News Letter',
MAX(CASE WHEN f.fee_name = 'T-Shirt' THEN f.fee_amount END)
AS 'T-Shirt',
MAX(CASE WHEN f.fee_name = 'Party' THEN f.fee_amount END)
AS 'Party',
SUM(f.fee_amount) AS Total
FROM Students s
INNER JOIN stud_fee sf
ON s.Id = sf.stud_id
INNER JOIN fee f
ON sf.fee_id = f.id
GROUP BY s.school_id
Upvotes: 2