使用不同的条件，在同一个表的一个SQL查询中使用多个聚合函数

I'm working on creating a SQL query that will pull records from a table based on the value of two aggregate functions. These aggregate functions are pulling data from the same table, but with different filter conditions. The problem that I run into is that the results of the SUMs are much larger than if I only include one SUM function. I know that I can create this query using temp tables, but I'm just wondering if there is an elegant solution that requires only a single query.

我正在创建一个SQL查询，该查询将根据两个聚合函数的值从表中提取记录。这些聚合函数从同一个表中提取数据，但是使用不同的过滤条件。我遇到的问题是，这些求和的结果比只包含一个和函数的结果要大得多。我知道我可以使用临时表创建这个查询，但我想知道是否有一种优雅的解决方案只需要一个查询。

I've created a simplified version to demonstrate the issue. Here are the table structures:

我创建了一个简化版本来演示这个问题。下面是表格结构:

EMPLOYEE TABLE

EMPID
1
2
3

ABSENCE TABLE

EMPID   DATE       HOURS_ABSENT
1       6/1/2009   3
1       9/1/2009   1
2       3/1/2010   2

And here is the query:

这是查询:

SELECT
    E.EMPID
    ,SUM(ATOTAL.HOURS_ABSENT) AS ABSENT_TOTAL
    ,SUM(AYEAR.HOURS_ABSENT) AS ABSENT_YEAR

FROM
    EMPLOYEE E

    INNER JOIN ABSENCE ATOTAL ON
        ATOTAL.EMPID = E.EMPID

    INNER JOIN ABSENCE AYEAR ON
        AYEAR.EMPID = E.EMPID

WHERE
    AYEAR.DATE > '1/1/2010'

GROUP BY
    E.EMPID

HAVING
    SUM(ATOTAL.HOURS_ABSENT) > 10
    OR SUM(AYEAR.HOURS_ABSENT) > 3

Any insight would be greatly appreciated.

如有任何见解，我们将不胜感激。

3 个解决方案

#1

SELECT
    E.EMPID
    ,SUM(ABSENCE.HOURS_ABSENT) AS ABSENT_TOTAL
    ,SUM(case when year(Date) = 2010 then ABSENCE.HOURS_ABSENT else 0 end) AS ABSENT_YEAR

FROM
    EMPLOYEE E

    INNER JOIN ABSENCE ON
        ABSENCE.EMPID = E.EMPID

GROUP BY
    E.EMPID

HAVING
    SUM(ATOTAL.HOURS_ABSENT) > 10
    OR SUM(case when year(Date) = 2010 then ABSENCE.HOURS_ABSENT else 0 end) > 3

edit:

编辑:

It's not a big deal, but I hate repeating conditions so we could refactor like:

这没什么大不了的，但我讨厌重复的条件，所以我们可以重构:

Select * From
(
    SELECT
        E.EMPID
        ,SUM(ABSENCE.HOURS_ABSENT) AS ABSENT_TOTAL
        ,SUM(case when year(Date) = 2010 then ABSENCE.HOURS_ABSENT else 0 end) AS ABSENT_YEAR

    FROM
        EMPLOYEE E

        INNER JOIN ABSENCE ON
            ABSENCE.EMPID = E.EMPID

    GROUP BY
        E.EMPID
    ) EmployeeAbsences
    Where ABSENT_TOTAL > 10 or ABSENT_YEAR > 3

This way, if you change your case condition, it's in one spot only.

这样，如果你改变你的情况，它只是在一个地方。

#2

Group different things separately, join groups.

将不同的东西分开分组，加入组。

SELECT
  T.EMPID
  ,T.ABSENT_TOTAL
  ,Y.ABSENT_YEAR
FROM
    (
    SELECT
        E.EMPID
        ,SUM(A.HOURS_ABSENT) AS ABSENT_TOTAL
    FROM
        EMPLOYEE E
        INNER JOIN ABSENCE A ON A.EMPID = E.EMPID
    GROUP BY
        E.EMPID
    ) AS T
    INNER JOIN
    (
    SELECT
        E.EMPID
        ,SUM(A.HOURS_ABSENT) AS ABSENT_YEAR
    FROM
        EMPLOYEE E
        INNER JOIN ABSENCE A ON A.EMPID = E.EMPID
    WHERE
        A.DATE > '1/1/2010'
    GROUP BY
        E.EMPID
    ) AS Y
    ON T.EMPLID = Y.EMPLID
WHERE
    ABSENT_TOTAL > 10 OR ABSENT_YEAR > 3

Also, if only SQL keywords are caps and the rest is not, readability increases. IMHO.

而且，如果只有SQL关键字是大写的，其余的不是，可读性就会增强。恕我直言。

#3

SELECT E.EMPID , sum(ABSENT_TOTAL) , sum(ABSENT_YEAR)
FROM
(SELECT 
    E.EMPID 
    ,SUM(ATOTAL.HOURS_ABSENT) AS ABSENT_TOTAL 
    ,0 AS ABSENT_YEAR 

FROM 
    EMPLOYEE E 

    INNER JOIN ABSENCE ATOTAL ON 
        ATOTAL.EMPID = E.EMPID 
WHERE 
    AYEAR.DATE > '1/1/2010' 

GROUP BY 
    E.EMPID 

HAVING 
    SUM(ATOTAL.HOURS_ABSENT) > 10 

 UNION ALL

 SELECT 0    
    ,SUM(AYEAR.HOURS_ABSENT) 
 FROM 
    EMPLOYEE E    

       INNER JOIN ABSENCE AYEAR ON 
        AYEAR.EMPID = E.EMPID 

GROUP BY 
    E.EMPID 

HAVING  
    SUM(AYEAR.HOURS_ABSENT) > 3) a

    GROUP BY A.EMPID