如何结合多个结果？

Question

我有一个查询，它返回受让人的门票总数：

SELECT DISTINCT case
    when ASSIGNEE LIKE '%e474728%' then 'Jason'
    when ASSIGNEE LIKE '%e499653%' then 'Alexis'
    when ASSIGNEE LIKE '%e509255%' then 'David'
    when ASSIGNEE LIKE '%e533676%' then 'KC Lin'
    when ASSIGNEE LIKE '%Desktop_Support%' then 'LIKE Desktop Support'
    when ASSIGNEE = 'Desktop_Support' then 'Desktop Support (unknown)'
else 'ASSIGNEE UNKNOWN'

End as ASSIGNEE,

COUNT(STATUS) as tickets
FROM techsupport
WHERE STATUS = 'Closed'
AND ASSIGNEE LIKE '%Desktop_Support%'

GROUP BY ASSIGNEE

WHICH产生结果：

ASSIGNEE                    tickets

Desktop Support (unknown)   981
David                       445
Alexis                      135
Jason                       48
KC Lin                      20
ASSIGNEE UNKNOWN            19
KC Lin                      18
Alexis                      15
Alexis                      14
KC Lin                      12
David                       11
ASSIGNEE UNKNOWN            11
Alexis                      10
Alexis                      8
ASSIGNEE UNKNOWN            7
Alexis                      4
Jason                       4
ASSIGNEE UNKNOWN            4

如何组合各种受让人？

这样它显示了每个受让人的合计总数？

ASSIGNEE                    tickets

Desktop Support (unknown)   981
David                       456
Jason                       52
KC Lin                      50
ASSIGNEE UNKNOWN            41
Alexis                      186

谢谢！

Answer 1

您正在通过ASSIGNEE进行分组，而不是通过案例表达式的结果进行分组（重命名是在分组后执行的）。另外明显是多余的，这里有一种方法可以不重复group by子句中的情况：

SELECT ASSIGNEE, count(status)
FROM (
    SELECT case when ASSIGNEE LIKE '%e474728%' then 'Jason'
                when ASSIGNEE LIKE '%e499653%' then 'Alexis'
                when ASSIGNEE LIKE '%e509255%' then 'David'
                when ASSIGNEE LIKE '%e533676%' then 'KC'
                when ASSIGNEE LIKE '%Desktop_Support%' then 'LIKE Desktop Support'
                when ASSIGNEE = 'Desktop_Support' then 'Desktop Support (unknown)'
                else 'ASSIGNEE UNKNOWN'
           End as ASSIGNEE
         , STATUS
    FROM techsupport
    WHERE STATUS = 'Closed'
) as X 
GROUP BY ASSIGNEE;

Answer 2

为case的别名使用其他名称，以区别于原始列名。

SELECT DISTINCT case
    when ASSIGNEE LIKE '%e474728%' then 'Jason'
    when ASSIGNEE LIKE '%e499653%' then 'Alexis'
    when ASSIGNEE LIKE '%e509255%' then 'David'
    when ASSIGNEE LIKE '%e533676%' then 'KC'
    when ASSIGNEE LIKE '%Desktop_Support%' then 'LIKE Desktop Support'
    when ASSIGNEE = 'Desktop_Support' then 'Desktop Support (unknown)'
else 'ASSIGNEE UNKNOWN'

End as ASSIGNEE_GRP,

COUNT(STATUS) as tickets
FROM techsupport
WHERE STATUS = 'Closed'
AND ASSIGNEE LIKE '%Desktop_Support%'

GROUP BY ASSIGNEE_GRP

Answer 3

SELECT语句的逻辑处理顺序：

1. FROM
2. ON
3. OUTER
4. WHERE
5. GROUP BY
6. CUBE | ROLLUP
7. HAVING
8. 选择
9. DISTINCT 10订购
10. TOP

如果你知道这一点，你就会理解为什么受让人会被重复。

Answer 4

在查询中尝试group by子句。 group by assignee