mysql - 如何使用间隔中的年和月动态显示一行中的零？

Question

我正在尝试创建一个查询以在 SET YEAR and MONTH 时以 12 个月的间隔显示计数(年和月是动态值 - 间隔是 12 个月的静态值).

例如:设置月 = 12 和年 = 2013

This will count from 2013-12-01 to 2014-11-30

其他示例:设置月 = 1 和年 = 2014

This will count from 2014-01-01 to 2014-12-31

我创建了这个 demo但也想在行数不在表中时显示 0，这里我使用了 COALESCE:

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

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

SELECT COALESCE(count(created_at), 0) AS count_all,
       year(created_at) as actual_year,
       month(created_at)as actual_month 
FROM creations
WHERE created_at BETWEEN @from AND @to
GROUP BY month(created_at),year(created_at)
ORDER BY year(created_at),month(created_at) ASC

但不幸的是得到了这个结果:

count_all   actual_year actual_month
1               2013         12
3               2014          1
2               2014          2
1               2014          3
1               2014          4
1               2014          5
1               2014          6
2               2014          8
1               2014          9
1               2014         10
1               2014         11

我期望这样的结果:

count_all   actual_year actual_month
1               2013         12
3               2014          1
2               2014          2
1               2014          3
1               2014          4
1               2014          5
1               2014          6
0               2014          7     <------ HERE I WANT 0 WHEN IS NOT IN DB
2               2014          8
1               2014          9
1               2014         10
1               2014         11

我创建了这个 live demo using month = 12 and year = 2013 ，它确实有效，但在测试和更改月份或年份值后，得到了错误的计数，因此查询无法正常工作，例如这个 demo using month= 1 and year =2013 isn't working correctly

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(@from, INTERVAL 12 MONTH);

SELECT IFNULL(counter,0) as counter, literals.y AS actual_year, literals.m AS actual_month
FROM (
  SELECT @var_month AS m, @var_year + 0 AS y
  UNION SELECT IF((@var_month + 1) % 12, (@var_month + 1) % 12, 12) AS m, @var_year + ((@var_month + 1) DIV 12) AS y
  UNION SELECT IF((@var_month + 2) % 12, (@var_month + 2) % 12, 12) AS m, @var_year + ((@var_month + 2) DIV 12) AS y
  UNION SELECT IF((@var_month + 3) % 12, (@var_month + 3) % 12, 12) AS m, @var_year + ((@var_month + 3) DIV 12) AS y
  UNION SELECT IF((@var_month + 4) % 12, (@var_month + 4) % 12, 12) AS m, @var_year + ((@var_month + 4) DIV 12) AS y
  UNION SELECT IF((@var_month + 5) % 12, (@var_month + 5) % 12, 12) AS m, @var_year + ((@var_month + 5) DIV 12) AS y
  UNION SELECT IF((@var_month + 6) % 12, (@var_month + 6) % 12, 12) AS m, @var_year + ((@var_month + 6) DIV 12) AS y
  UNION SELECT IF((@var_month + 7) % 12, (@var_month + 7) % 12, 12) AS m, @var_year + ((@var_month + 7) DIV 12) AS y
  UNION SELECT IF((@var_month + 8) % 12, (@var_month + 8) % 12, 12) AS m, @var_year + ((@var_month + 8) DIV 12) AS y 
  UNION SELECT IF((@var_month + 9) % 12, (@var_month + 9) % 12, 12) AS m, @var_year + ((@var_month + 9) DIV 12) AS y
  UNION SELECT IF((@var_month +10) % 12, (@var_month +10) % 12, 12) AS m, @var_year + ((@var_month +10) DIV 12) AS y
  UNION SELECT IF((@var_month +11) % 12, (@var_month +11) % 12, 12) AS m, @var_year + ((@var_month +11) DIV 12) AS y)  
  AS literals
  LEFT JOIN
  (SELECT count(*) as counter, year(created_at) y, month(created_at) as m 
   FROM creations WHERE created_at BETWEEN @from AND @to GROUP BY month(created_at),year(created_at)
   ORDER BY year(created_at),month(created_at) ASC 
 ) AS counts
 ON literals.m = counts.m AND literals.y = counts.y;

我花了几个月的时间搜索有关如何处理这个问题的信息。

如果有人可以帮助我，是无法解决还是其他技巧或查询？

Answer 1

不错的拼图:)

您可以生成一个表，其中包含 12 个月间隔所需的年和月，然后对其进行外部联接:

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

将给予:

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

那么试试这个(以 2014 年为年，1 为月的示例):

SQL Fiddle

MySQL 5.5 架构设置:

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')         
;

**查询**:

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

Results :

| 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 |

已编辑:

您也可以创建表而不是每次都在子查询中生成它:

SQL Fiddle

MySQL 5.5 架构设置:

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)
;

查询:

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

Results :

| 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 |