Hoe kun je nul op een rij weergeven met jaar- en maanddynamiek in een interval?

Leuke puzzel :)

U kunt een tabel genereren die het jaar en de maand bevat die nodig zijn voor het interval van 12 maanden en er vervolgens een outer join op uitvoeren:

SET @var_year = '2013'
SET @var_month = '12'

SELECT @row := @row + (case when right(@row,2) = "12" then 89 else 1 end) as YearMonth 
FROM 
(select 0 union all select 1 union all select 3 union all 
 select 4 union all select 5 union all select 6 union all 
 select 6 union all select 7 union all select 8 union all 
 select 9 union all select 10 union all select 11) t,
(SELECT @row:=CONCAT(@var_year,right(concat('0',(@var_month-1)),2))) r

Zal geven:

| YearMonth |
|-----------|
|    201312 |
|    201401 |
|    201402 |
|    201403 |
|    201404 |
|    201405 |
|    201406 |
|    201407 |
|    201408 |
|    201409 |
|    201410 |
|    201411 |

Dus probeer dit eens (voorbeeld met 2014 als jaar en 1 als maand):

SQL Fiddle

MySQL 5.5 Schema-instellingen :

CREATE TABLE creations(`id` int, `created_at` date )
;

INSERT INTO creations
    (`id`, `created_at`)
VALUES
    (1, '2013-12-11'),
    (2, '2014-01-11'),
    (3, '2014-01-21'),
    (4, '2014-01-12'),
    (5, '2014-02-22'),    
    (6, '2014-02-13'),
    (7, '2014-03-12'),    
    (8, '2014-04-23'),
    (9, '2014-05-23'),
    (10,'2014-06-23'),
    (11,'2014-08-23'),    
    (12,'2014-08-23'),
    (13,'2014-09-23'),
    (14,'2014-10-23'),    
    (15,'2014-11-23'),        
    (16,'2014-12-23')         
;

**Vraag **:

SET @var_year = '2014'
SET @var_month = '1'

SELECT count(created_at) AS count_all,
       left(YearMonth,4) as actual_year,
       right(YearMonth,2) as actual_month 
FROM (
SELECT @row := @row + (case when right(@row,2) = "12" then 89 else 1 end) as YearMonth FROM 
(select 0 union all select 1 union all select 3 union all 
 select 4 union all select 5 union all select 6 union all 
 select 6 union all select 7 union all select 8 union all 
 select 9 union all select 10 union all select 11) t,
(SELECT @row:=CONCAT(@var_year,right(concat('0',(@var_month-1)),2))) r
) as YearMonthTable
LEFT OUTER JOIN creations ON
  CONCAT(year(created_at),right(concat('0',month(created_at)),2)) = YearMonth
GROUP BY YearMonth
ORDER BY YearMonth ASC

Resultaten :

| count_all | actual_year | actual_month |
|-----------|-------------|--------------|
|         3 |        2014 |           01 |
|         2 |        2014 |           02 |
|         1 |        2014 |           03 |
|         1 |        2014 |           04 |
|         1 |        2014 |           05 |
|         1 |        2014 |           06 |
|         0 |        2014 |           07 |
|         2 |        2014 |           08 |
|         1 |        2014 |           09 |
|         1 |        2014 |           10 |
|         1 |        2014 |           11 |
|         1 |        2014 |           12 |

BEWERKT:

U kunt de tabel ook maken in plaats van deze elke keer in een subquery te genereren:

SQL Fiddle

MySQL 5.5 Schema-instellingen :

CREATE TABLE YearMonthTable(`tblYear` int, `tblMonth` int)
;

INSERT INTO YearMonthTable
    (`tblYear`,`tblMonth`)
VALUES
    (2013,12),
    (2014,1),
    (2014,2),    
    (2014,3),    
    (2014,4),
    (2014,5),
    (2014,6),
    (2014,7),    
    (2014,8),
    (2014,9),
    (2014,10),    
    (2014,11),        
    (2014,12),
    (2015,1),
    (2015,2),    
    (2015,3),    
    (2015,4),
    (2015,5)
;

Zoekopdracht :

SET @var_year = '2014'
SET @var_month = '1'

SET @from = STR_TO_DATE(CONCAT(@var_year, '/', @var_month, '/01'), '%Y/%m/%d')
SET @to = DATE_ADD(DATE_ADD(@from, INTERVAL 12 MONTH), INTERVAL -1 DAY)

SELECT count(created_at) AS count_all,
       tblYear as actual_year,
       tblMonth as actual_month 
FROM YearMonthTable
LEFT OUTER JOIN creations ON year(created_at) = tblYear AND 
                             month(created_at) = tblMonth
WHERE STR_TO_DATE(CONCAT(tblYear, '/', tblMonth, '/01'), '%Y/%m/%d') 
                                                    BETWEEN @from AND @to                               
GROUP BY tblMonth, tblYear
ORDER BY tblYear, tblMonth

Resultaten :

| count_all | tblYear | tblMonth |
|-----------|---------|----------|
|         3 |    2014 |        1 |
|         2 |    2014 |        2 |
|         1 |    2014 |        3 |
|         1 |    2014 |        4 |
|         1 |    2014 |        5 |
|         1 |    2014 |        6 |
|         0 |    2014 |        7 |
|         2 |    2014 |        8 |
|         1 |    2014 |        9 |
|         1 |    2014 |       10 |
|         1 |    2014 |       11 |
|         1 |    2014 |       12 |