Question

First_table

srno  wono   Actual_Start_Date  Actual_End_Date
1      31     2012-06-02         2012-06-05
2      32     2012-06-05         2012-06-22
3      33     2012-06-11         2012-06-23
4      34     2012-06-23         2012-06-30
5      A-2    2012-06-24         2012-06-25
6      BU     2012-06-24         2012-06-26
7      40     2012-06-25         2012-06-27

second_table

srno  wono    Base_start_date     Base_end_date    uploadhistoryid
1     31       2012-06-05            2012-06-05           1
2     32       2012-06-11            2012-06-12           2
3     32       2012-06-15            2012-06-17           3
4     32       2012-06-18            2012-06-20           4
5     33       2012-06-22            2012-06-25           5
5     33       2012-06-23            2012-06-25           5

结果必需

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER PROCEDURE [dbo].[Reports_Subanalysis]
(
@WONo VARCHAR(20)
)
AS
BEGIN

SELECT   
          'SAT' AS stage,
                   s.Base_start_date   AS start_date,
                   s.Base_end_date   AS  end_date,
                   f.Actual_Start_Date   AS Actual_Start_Date,
                   f.Actual_end_Date   AS Actual_End_Date
                   FROM First_table f,
                   second_table B
                   WHERE A.wOno=B.nOno
                   AND f.uploadhistoryid in (SELECT min(uploadhistoryid) FROM second_table C WHERE f.wono = C.wono)
                   AND b.wono=@WONo

END

当我通过'32'时

结果

stage    start_date     end_date      Actual_Start_Date   Actual_End_Date

SAT      2012-06-11     2012-06-12      2012-06-05          2012-06-05

当我传递非匹配值（如'BU'

）时，如何得到这样的结果？

stage    start_date     end_date      Actual_Start_Date   Actual_End_Date
SAT       NULL           NULL         2012-06-24           2012-06-26

我的日常生活中需要做哪些修改？

Answer 1

您需要使用左连接加入第二个表。也可以使用 - f .wono = @ WONo

SELECT TOP 1             
 'SAT' AS stage,                    
  s.Base_start_date   AS start_date,                    
  s.Base_end_date   AS  end_date,                    
  f.Actual_Start_Date   AS Actual_Start_Date,                    
  f.Actual_end_Date   AS Actual_End_Date                    
FROM First_table f                    
LEFT JOIN second_table s ON f.wOno=s.nOno
WHERE
f.wono=@WONo 
ORDER BY s.uploadhistoryid ASC

查询连接两个可能的多个映射表

1 个答案: