Question

我有这个查询

SELECT userId, orgQuery.timeUnit, 
  @SUM := @SUM + orgQuery.orderValue AS sum, 
  @COUNT := @COUNT + 1 AS count, 
  @AVG := @SUM / @COUNT AS avg
    FROM (
    SELECT userid, orderValue,  
      DATE_FORMAT(`acceptDate`, '%Y%M') AS timeUnit
FROM `agreements` 
    WHERE userId = 4 
    AND acceptDate > 2000-00-00 
   GROUP BY timeUnit
)
AS orgQuery, 
  (SELECT @COUNT := 0, @SUM := 0,@AVG :=0) 
 AS extra GROUP BY timeUnit

输出：

userId  timeUnit    sum count   avg
4         201001    6000    1   6000.0000
4         201003    12000   2   6000.0000
4         201004    19500   3   6500.0000

但正如您所看到的，某些日期之间存在差距，我希望输出为连续范围，例如：

userId  timeUnit    sum count   avg
4         201001    6000    1   6000.0000
4         201002    0       2   3000.0000
4         201003    12000   3   6000.0000
4         201004    19500   4   4875.0000

此查询

(SELECT DATE_FORMAT(`acceptDate`, '%Y%M') AS timeUnit FROM `agreements` GROUP BY timeUnit )

输出完整的日期范围，但是当我尝试LEFT JOIN这两个Querys时，count和avg都搞砸了。我怎样才能得到我想要的结果？

Answer 1

假设您在2012-02的协议表中缺少一个条目，那么拥有一个仅包含日期的表总是好的。

CREATE TABLE dates(`date` date primary key);

DROP PROCEDURE IF EXISTS insertDates;
DELIMITER $$
CREATE PROCEDURE insertDates()
BEGIN
SET @start_date = '2010-01-01';
WHILE (@start_date <= '2010-12-31') DO
INSERT INTO dates VALUES (@start_date);
SET @start_date:=DATE_ADD(@start_date, INTERVAL 1 DAY);
END WHILE;
END $$
DELIMITER ;

CALL insertDates();

根据您的需要调整日期范围。

然后您可以编写如下查询。我简化了一下，因为我看不到你的变量或子查询。

SELECT userId, DATE_FORMAT(dates.`date`, '%Y%M') AS timeUnit, 
  SUM(orderValue), 
  COUNT(orderValue),
  AVG(orderValue)
FROM 
dates LEFT JOIN
`agreements` ON dates.date = agreements.acceptDate
  WHERE userId = 4 
  AND acceptDate > '2000-00-00'
GROUP BY userId, timeUnit

<强>更新

SELECT userId, orgQuery.timeUnit, 
  @SUM := @SUM + orgQuery.orderValue AS sum, 
  @COUNT := @COUNT + 1 AS count, 
  @AVG := @SUM / @COUNT AS avg
    FROM (
    SELECT userid, orderValue,  
      DATE_FORMAT(dates.`date`, '%Y%M') AS timeUnit
FROM dates LEFT JOIN
`agreements` ON dates.date = agreements.acceptDate
    WHERE userId = 4 
    AND acceptDate > '2000-00-00' 
   GROUP BY timeUnit
)
AS orgQuery, 
  (SELECT @COUNT := 0, @SUM := 0,@AVG :=0) 
 AS extra GROUP BY timeUnit

如何LEFT JOIN，创建日期范围？

1 个答案: