Sql 聚合函数的Where子句条件
我有一个简单的问题Sql 聚合函数的Where子句条件,sql,sql-server,tsql,Sql,Sql Server,Tsql,我有一个简单的问题 SELECT US_LOGON_NAME as Username, COUNT(I.IS_ISSUE_NO) as Issues FROM ISSUES I JOIN USERS U ON I.IS_ASSIGNED_USER_ID = U.US_USER_ID WHERE I.IS_RECEIVED_DATETIME BETWEEN 20110101000000 AND 20110107000000 GROUP BY U.US_LOGON_NAME; 我想在选择列表中
SELECT US_LOGON_NAME as Username,
COUNT(I.IS_ISSUE_NO) as Issues
FROM ISSUES I JOIN USERS U ON I.IS_ASSIGNED_USER_ID = U.US_USER_ID
WHERE I.IS_RECEIVED_DATETIME BETWEEN 20110101000000 AND 20110107000000
GROUP BY U.US_LOGON_NAME;
我想在选择列表中添加额外的COUNT()函数,但对它们施加某些Where条件。这是用CASE()语句完成的吗?我尝试将Where子句放入select列表中,但这似乎是不允许的。我不确定这里是否真的需要子查询,但我不这么认为
例如,我需要一个COUNT()函数,该函数只计算某个范围内的问题,然后是另一个范围内的问题或其他组合条件下的问题,等等:
SELECT US_LOGON_NAME as Username,
COUNT(I.IS_ISSUE_NO (condition here)
COUNT(I.IS_ISSUE_NO (a different condition here)
等等
仍然按登录名分组
谢谢 一些解决方案
SELECT
SUM(CASE WHEN I.IS_ISSUE_NO (condition here) THEN 1 ELSE 0 END) AS COND1
SUM(CASE WHEN I.IS_ISSUE_NO (condition here) THEN 1 ELSE 0 END) AS COND2
您可以利用SQL不计算空值这一事实:
SELECT US_LOGON_NAME as Username,
COUNT(CASE WHEN <cond> THEN I.IS_ISSUE_NO ELSE NULL END)
COUNT(CASE WHEN <other cond> THEN I.IS_ISSUE_NO ELSE NULL END)
. . .
选择US\u LOGON\u NAME作为用户名,
计数(I.IS\U ISSUE\U NO ELSE NULL END时的情况)
计数(I.IS\U ISSUE\U NO ELSE NULL END时的情况)
. . .
或者您可以使用SUM而不是COUNT:
SELECT US_LOGON_NAME as Username,
SUM(CASE WHEN <cond> THEN 1 ELSE 0 END)
SUM(CASE WHEN <other cond> THEN 1 ELSE 0 END)
. . .
选择US\u LOGON\u NAME作为用户名,
总和(1或0结束时的情况)
总和(1或0结束时的情况)
. . .
在任何一种情况下,您都可以根据需要重复多次。该示例返回每个用户的计数,每个
IssueType
;
with
q_00 as (
select
is_issue_no
, is_assigned_user_id
, case
when is_issue_no between 1 and 10 then 'A'
when is_issue_no between 11 and 14 then 'B'
else 'C'
end as IssueType
from Issues
)
select
us_logon_name
, IssueType
, count(1) as cnt
from q_00 as a
join users as u on a.is_assigned_user_id = u.us_user_id
group by us_logon_name, IssueType
order by us_logon_name, IssueType ;
SQL server 2005+不计数也计数0?我以为只有
NULL
没有被计算。@柯克·沃尔:他的答案中哪里写着COUNT?是的,但亚当没有计算,他在求和。@Mark,哪里,诅咒我懒惰的阅读。:)我认为你的CASE
表达式可能是无效语法,因为没有END
。我认为你是对的,先生。我刚刚更新了语法。我们必须停止匆忙。