Grupo por mes en mysql incluso cuando los datos no están presentes - mysql

Digamos que tengo una tabla de "ventas" como abajo

Customer    Date    Amount
Paul    15/01/2015  2000
Jonathan    15/01/2015  3000
Taylor  15/01/2015  2000
Mark    15/01/2015  3000
Paul    15/02/2015  2000
Jonathan    15/02/2015  3000
Paul    25/02/2015  4000
Jonathan    25/02/2015  5000
Jonathan    15/03/2015  2000
Jonathan    25/04/2015  5000
Taylor  25/04/2015  4000
Mark    25/04/2015  5000
Paul    25/05/2015  4000
Jonathan    25/05/2015  5000
Taylor  25/05/2015  4000
Mark    25/05/2015  5000

Y en el informe quiero verlo como abajo -

Customer    Month   Amount
Paul    201501  2000
Paul    201502  6000
Paul    201503  0
Paul    201504  0
Paul    201505  4000

¿Por favor, dime cómo hacerlo?

Actualizar

Customer    Month   Amount
Paul    201501  2000
Paul    201502  6000
Paul    201503  0
Paul    201504  0
Paul    201505  4000
Jonathan    201501  3000
Jonathan    201502  8000
Jonathan    201503  2000
Jonathan    201504  5000
Jonathan    201505  5000
Taylor  201501  2000
Taylor  201502  0
Taylor  201503  0
Taylor  201504  4000
Taylor  201505  4000
Mark    201501  3000
Mark    201502  0
Mark    201503  0
Mark    201504  5000
Mark    201505  5000

También necesito hacer esta vista para todos los clientes. Por favor, dime cómo hacer eso.

Respuestas

1 para la respuesta № 1

Aquí hay una solución, con una demostración, usando la fecha que proporcionó. Además, se agregan más datos para la simulación.

caída de ventas de mesa;

SQL:

-- data
create table sales(Customer varchar(100), `Date` date, Amount int);
insert into sales values
("Paul",    "2015-01-15",  2000),
("Jonathan",    "2015-01-15",  3000),
("Taylor",  "2015-01-15",  2000),
("Mark",    "2015-01-15",  3000),
("Paul",    "2015-02-15",  2000),
("Jonathan",    "2015-02-15",  3000),
("Paul",    "2015-02-25",  4000),
("Jonathan",    "2015-02-25",  5000),
("Jonathan",    "2015-03-15",  2000),
("Jonathan",    "2015-04-15",  5000),
("Taylor",  "2015-04-25",  4000),
("Mark",    "2015-04-25",  5000),
("Paul",    "2015-05-25",  4000),
("Jonathan",    "2015-05-25",  5000),
("Taylor",  "2015-05-25",  4000),
("Mark",    "2015-05-25",  5000);
select * from sales;

-- query wanted
select
COALESCE(s.Customer, "") AS Customer, DATE_FORMAT(m2.cont_date, "%Y%m") AS Month, SUM(COALESCE(s.Amount, 0)) AS Amount
from (
select (select MAX(`Date`) from sales) - interval (year.b * 10 + month.a) MONTH AS cont_date
from (
select 0 b union select 1 union select 2 union select 3 union select 4 union
select 5 union select 6 union select 7 union select 8 union select 9) AS year
CROSS JOIN
(
select 0 a union select 1 union select 2 union select 3 union select 4 union
select 5 union select 6 union select 7 union select 8 union select 9) AS month
where (year.b * 10 + month.a) < (select timestampdiff(month, MIN(`Date`), MAX(`Date`)) + 1 from sales) ) m2
LEFT JOIN sales s ON s.Customer = "paul" AND DATE_FORMAT(m2.cont_date, "%Y%m") = DATE_FORMAT(s.`Date`, "%Y%m")
GROUP BY Month;

Salida:

mysql> select * from sales;
+----------+------------+--------+
| Customer | Date       | Amount |
+----------+------------+--------+
| Paul     | 2015-01-15 |   2000 |
| Jonathan | 2015-01-15 |   3000 |
| Taylor   | 2015-01-15 |   2000 |
| Mark     | 2015-01-15 |   3000 |
| Paul     | 2015-02-15 |   2000 |
| Jonathan | 2015-02-15 |   3000 |
| Paul     | 2015-02-25 |   4000 |
| Jonathan | 2015-02-25 |   5000 |
| Jonathan | 2015-03-15 |   2000 |
| Jonathan | 2015-04-15 |   5000 |
| Taylor   | 2015-04-25 |   4000 |
| Mark     | 2015-04-25 |   5000 |
| Paul     | 2015-05-25 |   4000 |
| Jonathan | 2015-05-25 |   5000 |
| Taylor   | 2015-05-25 |   4000 |
| Mark     | 2015-05-25 |   5000 |
+----------+------------+--------+
16 rows in set (0.00 sec)

mysql>
mysql> -- query wanted
mysql> select
->     COALESCE(s.Customer, "") AS Customer, DATE_FORMAT(m2.cont_date, "%Y%m") AS Month, SUM(COALESCE(s.Amount, 0)) AS Amount
-> from (
->     select (select MAX(`Date`) from sales) - interval (year.b * 10 + month.a) MONTH AS cont_date
->     from (
->         select 0 b union select 1 union select 2 union select 3 union select 4 union
->         select 5 union select 6 union select 7 union select 8 union select 9) AS year
->         CROSS JOIN
->         (
->         select 0 a union select 1 union select 2 union select 3 union select 4 union
->         select 5 union select 6 union select 7 union select 8 union select 9) AS month
->     where (year.b * 10 + month.a) < (select timestampdiff(month, MIN(`Date`), MAX(`Date`)) + 1 from sales) ) m2
->     LEFT JOIN sales s ON s.Customer = "paul" AND DATE_FORMAT(m2.cont_date, "%Y%m") = DATE_FORMAT(s.`Date`, "%Y%m")
-> GROUP BY Month;
+----------+--------+--------+
| Customer | Month  | Amount |
+----------+--------+--------+
| Paul     | 201501 |   2000 |
| Paul     | 201502 |   6000 |
|          | 201503 |      0 |
|          | 201504 |      0 |
| Paul     | 201505 |   4000 |
+----------+--------+--------+
5 rows in set (0.00 sec)

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0 para la respuesta № 2

Puedes crear una tabla en línea, con todos los meses, y luego unirte a tu tabla de ventas.

Algo como esto:

SELECT s.customer_name as Customer,
CONCAT(months.m, "-", years.y) as Month,
s.amount as Amount
FROM (
SELECT "01" AS m UNION ALL SELECT "02" UNION ALL SELECT "03" UNION ALL
SELECT "04" UNION ALL SELECT "05" UNION ALL SELECT "06" UNION ALL
SELECT "07" UNION ALL SELECT "08" UNION ALL SELECT "09" UNION ALL
SELECT "10" UNION ALL SELECT "11" UNION ALL SELECT "12") AS months
CROSS JOIN (
SELECT "2015" AS y UNION ALL SELECT "2016") AS years
LEFT JOIN sales_table AS s
ON DATE_FORMAT(s.date, "%Y-%c") = CONCAT(years.y, "-", months.m)
GROUP BY CONCAT(months.m, "-", years.y)

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