Question

我试图找到患者who are active on date 2016-05-01 but not active on date 2016-06-01，患者Z673032。见下表

pat_id  dm_date
-------------------------------
Z672385 2016-05-01 00:00:00.000
Z672385 2016-06-01 00:00:00.000
Z672444 2016-05-01 00:00:00.000
Z672444 2016-06-01 00:00:00.000
Z672570 2016-05-01 00:00:00.000
Z672570 2016-06-01 00:00:00.000
Z672995 2016-05-01 00:00:00.000
Z672995 2016-06-01 00:00:00.000
Z673032 2016-05-01 00:00:00.000

我的查询：

select A.pat_id 
from  A
where 
    A.dm_date = '2016-05-01'
    and A.PAT_ID not in (select B.pat_id 
                         from B
                         where B.dm_date = '2016-06-01')

但它返回Null。它应该是直截了当的但是......对此有何看法？我使用的是SQL Server Management Studio。

Answer 1

您需要在别名之前包含表名。

检查 demo fiddle

select A.pat_id 
from  Table1 A
where 
    A.dm_date = '2016-05-01'
and A.PAT_ID not in (select B.pat_id 
                     from Table1 B
                     where B.dm_date = '2016-06-01')

Answer 2

尝试将表格加入到自己中

SELECT a.pat_id 
FROM   a 
       LEFT JOIN b 
              ON a.pat_id = b.pat_id 
WHERE  a.dm_date BETWEEN '2016-05-01 00:00:00' AND '2016-05-01 23:59:59' 
       AND b.pat_date BETWEEN '2016-06-01 00:00:00' AND '2016-06-01 23:59:59'

在比较日期时间戳时，SQL Server可能会对如何解释日期感到挑剔。

尝试查找ID在某个时间不活动以跟踪一段时间

2 个答案: