How to dynamic pivot mysql table? - mysql

Question

Hi I've got the following mysql table:
I need to pivot these datas to look like the following:
The scadenza is not always the same and can change therefore I believe I need to create the pivot table dynamically, This is the stored procedure I've tried:
BEGIN
SELECT
GROUP_CONCAT(
CONCAT("MAX(IF(scadenza='", scadenza, "',importo ,'')) AS '", scadenza, "'"), "
"
)INTO #answers
FROM (
SELECT DISTINCT scadenza,
importo
FROM ripartizione_rate
) A;
SET #query :=
CONCAT(
'SELECT DISTINCT condomino, anagrafica,', #answers,
'FROM ripartizione_rate
GROUP BY condomino, anagrafica'
);
PREPARE statement FROM #query;
EXECUTE statement;
END
The result I get is very close but I get the date repeated as you can see in the image below:
Can please anyboby halp me to fix this problem? Many thanks for your help
This is the dump text for the table
INSERT INTO `ripartizione_rate` (`id`, `preventivo`, `piano_rateale`, `condomino`, `anagrafica`, `immobile`, `descrizione`, `scadenza`, `stato_pagamento`, `importo`, `importo_pagato`, `importo_residuo`) VALUES
(1, 1, 1, 19, 11, 3, 'Rata Num.1', '2021-01-01', 0, '208.38', '0.00', '0.00'),
(2, 1, 1, 12, 15, 3, 'Rata Num.1', '2021-01-01', 0, '208.38', '0.00', '0.00'),
(3, 1, 1, 10, 15, 5, 'Rata Num.1', '2021-01-01', 0, '500.10', '0.00', '0.00'),
(4, 1, 1, 20, 17, 3, 'Rata Num.1', '2021-01-01', 0, '83.35', '0.00', '0.00'),
(5, 1, 1, 19, 11, 3, 'Rata Num.2', '2021-05-01', 0, '208.31', '0.00', '0.00'),
(6, 1, 1, 12, 15, 3, 'Rata Num.2', '2021-05-01', 0, '208.31', '0.00', '0.00'),
(7, 1, 1, 10, 15, 5, 'Rata Num.2', '2021-05-01', 0, '499.95', '0.00', '0.00'),
(8, 1, 1, 20, 17, 3, 'Rata Num.2', '2021-05-01', 0, '83.33', '0.00', '0.00'),
(9, 1, 1, 19, 11, 3, 'Rata Num.3', '2021-09-01', 0, '208.31', '0.00', '0.00'),
(10, 1, 1, 12, 15, 3, 'Rata Num.3', '2021-09-01', 0, '208.31', '0.00', '0.00'),
(11, 1, 1, 10, 15, 5, 'Rata Num.3', '2021-09-01', 0, '499.95', '0.00', '0.00'),
(12, 1, 1, 20, 17, 3, 'Rata Num.3', '2021-09-01', 0, '83.33', '0.00', '0.00');

Answer 1

The subquery part here:
SELECT
GROUP_CONCAT(
CONCAT("MAX(IF(scadenza='", scadenza, "',importo ,'')) AS '", scadenza, "'"), "
"
)INTO #answers
FROM (
SELECT DISTINCT scadenza, <----
importo <---- this subquery
FROM ripartizione_rate <----
) A
returns the following result:
+------------+---------+
| scadenza | importo |
+------------+---------+
| 2021-01-01 | 208.38 |
| 2021-01-01 | 500.10 |
| 2021-01-01 | 83.35 |
| 2021-05-01 | 208.31 |
| 2021-05-01 | 499.95 |
| 2021-05-01 | 83.33 |
| 2021-09-01 | 208.31 |
| 2021-09-01 | 499.95 |
| 2021-09-01 | 83.33 |
+------------+---------+
Each date returns 3 rows due to the DISTINCT combination of scadenza, importo. If you run SELECT #answers; after the variable being assigned then you'll get:
SELECT #answers;
+-------------------------------------------------------------+
| #answers |
+-------------------------------------------------------------+
| MAX(IF(scadenza='2021-01-01',importo ,'')) AS '2021-01-01' |
| ,MAX(IF(scadenza='2021-01-01',importo ,'')) AS '2021-01-01' |
| ,MAX(IF(scadenza='2021-01-01',importo ,'')) AS '2021-01-01' |
| ,MAX(IF(scadenza='2021-05-01',importo ,'')) AS '2021-05-01' |
| ,MAX(IF(scadenza='2021-05-01',importo ,'')) AS '2021-05-01' |
| ,MAX(IF(scadenza='2021-05-01',importo ,'')) AS '2021-05-01' |
| ,MAX(IF(scadenza='2021-09-01',importo ,'')) AS '2021-09-01' |
| ,MAX(IF(scadenza='2021-09-01',importo ,'')) AS '2021-09-01' |
| ,MAX(IF(scadenza='2021-09-01',importo ,'')) AS '2021-09-01' |
+-------------------------------------------------------------+
Whereas what you really want is just 3 distinctive dates instead of 3x3 distinctive dates. Therefore, the fix is quite simple really, you just need to remove the column importo from the subquery:
SELECT
GROUP_CONCAT(
CONCAT("MAX(IF(scadenza='", scadenza, "',importo ,'')) AS '", scadenza, "'"), "") INTO #answers
FROM (SELECT DISTINCT scadenza
FROM ripartizione_rate
) A;
SELECT #answers;
SET #query :=
CONCAT(
'SELECT DISTINCT condomino, anagrafica,', #answers2,
'FROM ripartizione_rate
GROUP BY condomino, anagrafica
ORDER BY condomino, anagrafica'
);
SELECT #query;
PREPARE statement FROM #query;
EXECUTE statement;
Demo fiddle