Question

我有一个查询在哪里我需要从表中选择所有不同的ID，还需要只选择min（date），这样我就可以得到第一个插入的记录而不是所有日期的ID。

基本上这就是我要找的 -

表1 ||表2-
ID || ID日期

1 || 1 11/11/2010
1 || 1 10/11/2010
3 || 3 12/01/2010
4 || 4 01/01/2010
4 || 4 02/01/2010

所以我需要从表2中获取所有记录（table1.ID = table2.ID），其中包含最小日期和该ID

这里的结果将是 1 10/11/2010
3 12/01/2010
4 01/01/2010

这是我的查询

select u.firstName,u.lastName ,count(*) as theCount
from tbl_appts_change_log c,tbl_appts a, tbl_users u
where  c.appt_id=a.ID
and c.user_id=u.userID
 and c.appt_id in ( select  c.appt_id,min(c.date) from tbl_appts_change_log c, tbl_appts a
                        where  c.appt_id=a.ID
                        and a.satellite_id='160' GROUP BY c.appt_id)    
group by u.firstName,u.lastName
 order by count(*) desc,u.firstName,u.lastName

Answer 1

也许：

select u.firstName,u.lastName ,count(*) as theCount
from tbl_appts_change_log c
INNER JOIN tbl_appts a on c.appt_id=a.ID
INNER JOIN tbl_users u on c.user_id=u.userID
INNER JOIN ( select  c.appt_id,min(c.date) as LastDate 
    from tbl_appts_change_log c 
    INNER JOIN  tbl_appts a on  c.appt_id=a.ID
    Where a.satellite_id='160' GROUP BY c.appt_id) d
on c.appt_id = d.appt_id and c.date = d.LastDate
group by u.firstName,u.lastName
order by count(*) desc,u.firstName,u.lastName

Answer 2

我忽略了你的代码，因为它似乎与你在问题中所描述的情况完全不同，即表1和表2。如果您想要的只是每个ID的最短日期，那么

SELECT T1.ID,   MIN(T2.Date)
FROM Table1 T1
    JOIN Table2 T2 ON T1.ID = T2.ID
GROUP BY T1.ID

但我猜你真正想要的是这样的东西？

Table 1 || Table 2-
ID || ID Date Desc

1 || 1 11/11/2010 AAA
1 || 1 10/11/2010 BBB
3 || 3 12/01/2010 CCC
4 || 4 01/01/2010 DDD
4 || 4 02/01/2010 EEE

预期结果

1 10/11/2010 BBB
3 12/01/2010 CCC
4 01/01/2010 DDD

这比仅仅进行分组稍微复杂一些，有两种方法可以解决它。您可以尝试两者并查看哪一个表现最佳

方法1：使用行号

;WITH ResultCTE AS
(
    SELECT T2.ID, T2.Date, T2.Desc,
       RowNumber = ROW_NUMBER() OVER(PARTITION BY T2.ID ORDER BY T2.Date ASC)   
    FROM Table1 T1
          JOIN Table2 T2 ON T1.ID = T2.ID
)    
SELECT ID, Date, Desc
FROM ResultCTE    
WHERE RowNumber = 1

方法2：嵌套查询

;WITH ResultCTE AS
(
    SELECT T2.ID, MIN(T2.Date) AS Date
    FROM Table1 T1
        JOIN Table2 T2 ON T1.ID = T2.ID
    GROUP BY T2.ID
)
SELECT T.ID, T.Date, T.Desc
FROM Table2 T
    JOIN ResultCTE R
        ON R.ID = T.ID AND R.Date = T.Date

Answer 3

SELECT u.firstName,
  u.lastName ,
  COUNT(*) AS theCount
FROM tbl_appts_change_log c,
  tbl_appts a,
  tbl_users u
WHERE c.appt_id=a.ID
AND c.user_id  =u.userID
AND a.satellite_id = '160'
AND c.date = (SELECT MIN(ci.date)
  FROM tbl_appts_change_log ci,
    tbl_appts ai
  WHERE ci.appt_id   = ai.ID
  AND ci.appt_id = c.appt_id
  AND ai.satellite_id= a.satellite_id
  )
GROUP BY u.firstName,
  u.lastName
ORDER BY COUNT(*) DESC,
  u.firstName,
  u.lastName

Answer 4

select u.firstName,u.lastName,count(*) as theCount,cm.MinDate
from ( 
    select c.appt_id,min(c.date) as MinDate
    from tbl_appts_change_log c, tbl_appts a 
    where c.appt_id=a.ID 
        and a.satellite_id='160' 
    GROUP BY c.appt_id
    ) cm 
inner join tbl_appts_change_log c on cm.appt_id = c.appt_id and cm.MinDate = c.date 
inner join tbl_appts a on c.appt_id=a.ID 
inner join tbl_users u on c.user_id=u.userID 
group by u.firstName,u.lastName 
order by count(*) desc,u.firstName,u.lastName

Answer 5

如果您要寻找的是-

表1 ||表2-
ID ||身份证日期

1 || 1 11/11/2010
1 || 1 10/11/2010
3 || 3 12/01/2010
4 || 4 01/01/2010
4 || 4 02/01/2010

尝试使用此：

  def search(request):
    date = request.GET.get('date')

    queryset = List.objects.filter(date=date)
    data = serializers.serialize('json', queryset)

    return HttpResponse(data, content_type='application/json')

  def export_to_csv(request):
    data = search(request)
    # But that does not bring the search data
    print(data)
    # <HttpResponse status_code=200, "application/json">

Answer 6

这就是你要追求的吗？

select u.firstName,u.lastName ,count(*) as theCount
from tbl_appts_change_log c,tbl_appts a, tbl_users u
where  c.appt_id=a.ID
and c.user_id=u.userID
and a.satellite_id = '160'
and c.date = (
  select min(date) 
  from tbl_appts_change_log c, tbl_appts a
  where c.appt_id = a.id
  and a.satellite_id = '160'
)
group by u.firstName,u.lastName
order by count(*) desc,u.firstName,u.lastName

选择不同记录作为最小日期

6 个答案: