mysql sql 按天分组统计

天分组统计"/>

mysql sql 按天分组统计

mysql数据库，当我们按日期展示数据时，经常碰到日期时间段内某一天数据不存在，为空。这时候我们查询数据往如下图一样，时间数据发生间断，造成数据缺失，无法连续展示

所以可以加上下面的代码，进行一个链接查询，以时间为链接条件，可以将间断数据补全

SELECT

DATE_FORMAT(

CURDATE( ) - INTERVAL ( a.n + ( 10 * b.n ) + ( 100 * c.n ) ) DAY,

'%Y%m%d'

) AS date

FROM

(

SELECT

0 AS n UNION ALL

SELECT

1 UNION ALL

SELECT

2 UNION ALL

SELECT

3 UNION ALL

SELECT

4 UNION ALL

SELECT

5 UNION ALL

SELECT

6 UNION ALL

SELECT

7 UNION ALL

SELECT

8 UNION ALL

SELECT

9

) AS a

CROSS JOIN (

SELECT

0 AS n UNION ALL

SELECT

1 UNION ALL

SELECT

2 UNION ALL

SELECT

3 UNION ALL

SELECT

4 UNION ALL

SELECT

5 UNION ALL

SELECT

6 UNION ALL

SELECT

7 UNION ALL

SELECT

8 UNION ALL

SELECT

9

) AS b

CROSS JOIN (

SELECT

0 AS n UNION ALL

SELECT

1 UNION ALL

SELECT

2 UNION ALL

SELECT

3 UNION ALL

SELECT

4 UNION ALL

SELECT

5 UNION ALL

SELECT

6 UNION ALL

SELECT

7 UNION ALL

SELECT

8 UNION ALL

SELECT

9

) AS c

WHERE

(

CURDATE( ) - INTERVAL ( a.n + ( 10 * b.n ) + ( 100 * c.n ) ) DAY

) > ( CURDATE( ) - INTERVAL 24 MONTH )

以该语句进行连接查询，如图

MySQL实现按天分组统计，提供完整日期列表，无数据自动补0

SELECT

DATE_FORMAT(CURDATE() - INTERVAL (a.n + (10 * b.n)) MONTH, '%Y%m') AS date

FROM (

SELECT 0 AS n UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4

UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9

) AS a CROSS JOIN (

SELECT 0 AS n UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4

UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9

) AS b

WHERE (CURDATE() - INTERVAL (a.n + (10 * b.n)) MONTH) > (CURDATE() - INTERVAL 24 MONTH)

MySQL实现按月分组统计，提供完整日期列表，无数据自动补0

上述是俩个例子，大家可以根据具体情况自由组合发挥。上述是目前楼主发现的方法，可能还有其他更好方法，希望可以分享给楼主我，谢谢