Question

我有这个简单的查询（TSQL） -

SELECT IdTour, Tour, TourOrder, IdContent
    FROM View_ToursListContentId
    WHERE (IdContent = 3) OR (IdContent = 4)
    ORDER BY TourOrder DESC, Tour

结果如下

58  Air & Style Tour                   2015/16  NULL    3
48  FIS Europa Cup                     2015/16  NULL    3
46  FIS World Cup Tour                 2015/16  NULL    3
131 KDC Grand Slam Regional Qualifiers 2016     NULL    3
59  Swatch Freeride World Tour         2016     NULL    3
77  World Rookie Tour                  2015/16  NULL    3
57  World Snowboard Tour               2015/16  NULL    3
45  X Games                            2016     NULL    3
45  X Games                            2016     NULL    4

我需要做的是。如果在内部结果IdTour与IdContent = 3不要显示相同的IdTour与IdContent = 4.（显示IdTour与IdContent = 4，如果没有相同的IdTour与IdContent = 3 - 在我的情况下只显示一个IdTour 45与IdContent 3）

最简单，最快捷的方法是什么，我怎么能完成它？

Thanx很多

Answer 1

一种方法涉及使用NOT EXISTS：

SELECT IdTour, Tour, TourOrder, IdContent
FROM View_ToursListContentId t1
WHERE (IdContent = 3) OR 
      ((IdContent = 4) AND NOT EXISTS (SELECT 1
                                       FROM View_ToursListContentId t2
                                       WHERE t1.IdTour = t2.IdTour AND
                                             t2.IdContent = 3))
ORDER BY TourOrder DESC, Tour

如果存在具有相同NOT EXISTS和IdContent = 4的记录，则IdTour运算符会过滤掉IdContent = 3的记录。

Answer 2

您可以使用窗口函数获取IdContent可用的最低IdTour：

SELECT  IdTour, 
        Tour, 
        TourOrder, 
        IdContent,
        MinIdContent = MIN(IdContent) OVER(PARTITION BY IdTour)
FROM    View_ToursListContentId
WHERE   IdContent IN (3, 4);

然后如果这是3然后你只选择3，如果它是4然后你只选择4，或者更简单，只选择匹配最小值的IdContent：

SELECT  IdTour, Tour, TourOrder, IdContent
FROM    (   SELECT  IdTour, 
                    Tour, 
                    TourOrder, 
                    IdContent,
                    MinIdContent = MIN(IdContent) OVER(PARTITION BY IdTour)
            FROM    View_ToursListContentId
            WHERE   IdContent IN (3, 4)
        ) AS t
WHERE   IdContent = MinIdContent;

完整示例

WITH View_ToursListContentId AS
(   SELECT  IdTour, Tour, TourOrder, IdContent
    FROM    (VALUES
                (58, 'Air & Style Tour 2015/16', NULL, 3),
                (48, 'FIS Europa Cup 2015/16', NULL, 3),
                (46, 'FIS World Cup Tour 2015/16', NULL, 3),
                (131, 'KDC Grand Slam Regional Qualifiers 2016', NULL, 3),
                (59, 'Swatch Freeride World Tour 2016', NULL, 3),
                (77, 'World Rookie Tour 2015/16', NULL, 3),
                (57, 'World Snowboard Tour 2015/16', NULL, 3),
                (45, 'X Games 2016', NULL, 3),
                (45, 'X Games 2016', NULL, 4)
            ) t (IdTour, Tour, TourOrder, IdContent)
)
SELECT  IdTour, Tour, TourOrder, IdContent
FROM    (   SELECT  IdTour, 
                    Tour, 
                    TourOrder, 
                    IdContent,
                    MinIdContent = MIN(IdContent) OVER(PARTITION BY IdTour)
            FROM    View_ToursListContentId
            WHERE   IdContent IN (3, 4)
        ) AS t
WHERE   IdContent = MinIdContent;

Answer 3

select * from (
select row_number() over (partition by IdTour, Tour, TourOrder order by IdContent) rownum,
IdTour, Tour, TourOrder, IdContent from View_ToursListContentId)src
where rownum=1

Answer 4

您应该在查询中使用group by IdContent 喜欢

SELECT IdTour, Tour, TourOrder, IdContent
    FROM View_ToursListContentId
    WHERE (IdContent = 3) OR (IdContent = 4)
group by IdContent
    ORDER BY TourOrder DESC, Tour

SELECT查询中的第二个条件

4 个答案: