1

鉴于这些表

table Channel
--------------
ChannelID int IDENTITY
<other irrelevant stuff>

table Program
--------------
ProgramID   int IDENTITY
ChannelID   int
AiringDate  datetime
<other irrelevant stuff>

这个查询

SELECT   C.ChannelID, t.AiringDate
FROM 
Channel C
LEFT JOIN ( 
    SELECT distinct ChannelID
    FROM   Program 
    WHERE AiringDate = '2010-01-16'
) p 
        ON p.ChannelID=C.ChannelID 
CROSS JOIN (
    SELECT AiringDate = '2010-01-16'
) t
WHERE   C.ChannelID IN (1, 2, 74, 15, 906)  /* the Channel table contains more channels than we are interested in */
    AND p.ChannelID IS NULL

产生

ChannelID | AiringDate
----------|-----------
    2     | 2010-01-16
   906    | 2010-01-16

如何修改它以接受日期范围，以便结果类似于

ChannelID | AiringDate
----------|-----------
    2     | 2010-01-16
   906    | 2010-01-16
    2     | 2010-01-17
   906    | 2010-01-17

如果这两天没有在这两个频道播出的节目

这不返回任何行

SELECT   C.ChannelID, t.AiringDate
FROM 
Channel C
LEFT JOIN ( 
    SELECT distinct ChannelID, AiringDate
    FROM   Program 
    WHERE AiringDate between '2010-01-16' and '2010-01-17'
) p 
        ON p.ChannelID=C.ChannelID 
CROSS JOIN (
    SELECT AiringDate = '2010-01-16'
    union
    SELECT AiringDate = '2010-01-17'
) t
WHERE   C.ChannelID IN (1, 2, 74, 15, 906) 
    AND p.ChannelID IS NULL

这CROSS JOIN有点难看，完全摆脱它会很好。请注意，第一个示例查询有点复杂；对于单个日期，我有一个更简单的日期，它只输出缺少的 ChannelID：

SELECT   C.ChannelID
FROM 
Channel C
LEFT JOIN ( 
    SELECT distinct ChannelID
    FROM   Program 
    WHERE  AiringDate = '2010-01-16'
) p 
        ON p.ChannelID=C.ChannelID 
WHERE   C.ChannelID IN (1, 2, 74, 15, 906) 
    AND p.ChannelID IS NULL
4

1 回答 1

2

如果我理解正确，这应该得到您的要求。

  • 将所有频道与每个 AiringDate 结合起来
  • 选择您需要的日期之间具有 AiringDates 的所有频道。
  • LEFT JOIN删除所有已经有 AiringDates 的频道

SQL 语句

DECLARE @Channel TABLE (ChannelID INTEGER PRIMARY KEY)
DECLARE @Program TABLE (ProgramID INTEGER PRIMARY KEY, ChannelID INTEGER, AiringDate DATETIME)

INSERT INTO @Channel VALUES (1) -- Aired on 16 & 17
INSERT INTO @Channel VALUES (2) -- Aired on 16
INSERT INTO @Channel VALUES (3) -- Not Aired

INSERT INTO @Program VALUES (1, 1, '01-16-2010')
INSERT INTO @Program VALUES (2, 1, '01-17-2010')
INSERT INTO @Program VALUES (3, 2, '01-16-2010')


SELECT  C.*
FROM    (
          SELECT  C.ChannelID 
                  , p.AiringDate 
          FROM    @Channel C        
                  CROSS JOIN ( 
                    SELECT  DISTINCT AiringDate 
                    FROM    @Program 
                    WHERE   AiringDate BETWEEN '01-16-2010' AND '01-17-2010'
                  ) p 
        ) c
        LEFT OUTER JOIN (
          SELECT  C.ChannelID, p.AiringDate
          FROM    @Channel C
                  INNER JOIN @Program p ON p.ChannelID = C.ChannelID
          WHERE   AiringDate BETWEEN '01-16-2010' AND '01-17-2010' 
        ) p ON p.ChannelID = C.ChannelID AND p.AiringDate = C.AiringDate
WHERE   p.ChannelID IS NULL AND p.AiringDate IS NULL
于 2010-02-23T09:23:08.010 回答