SQL Server 数据透视表帮助

Question

我正在尝试转下面的ResultSet

Meetings Covers   Date         TypeName
1         3       2010-10-14   Breakfast
1         1       2010-10-14   LunchCooked
2         4       2010-10-15   Breakfast
1         3       2010-10-18   Breakfast
1         3       2010-10-19   Breakfast
1         1       2010-10-19   LunchSandwich
1         3       2010-10-20   Breakfast
1         3       2010-10-21   Breakfast
1         3       2010-10-22   Breakfast

转化为具有以下字段的格式

Date
BreakfastMeetings
BreakfastCovers
LunchSandwichMeetings
LunchSandwichCovers
LunchCookedMeetings
LunchCookedCovers

我认为这可以通过数据透视表完成吗？任何指针都会很好，否则我最终将采用某种 hacky 临时表路由来将数据转换为这种格式。

谢谢

Answer 1

这是一种方法。它实际上需要和 unpivot 和一个 pivot 操作。 unpivot 将 Meetings 和 Covers 合并到一个列中，并将 TypeName 值更改为所需的列名。

pivot 使用 unpivot 的结果来提供最终格式。

SELECT TheDate, BreakfastMeetings, BreakfastCovers, LunchSandwichMeetings,
    LunchSandwichCovers, LunchCookedMeetings, LunchCookedCovers
FROM (
    -- unpivot to put counts in single column and create new type names
    SELECT TheDate, TypeName + MeetingCover AS TypeName, RowCounts
    FROM (SELECT TheDate, TypeName, Meetings, Covers
        FROM MyTable
        ) AS p
        UNPIVOT (RowCounts FOR MeetingCover IN (Meetings, Covers)
        ) AS UnpivotTable
    ) AS Source
    -- pivot the unpivoted data to create new columns
    PIVOT ( MAX(RowCounts) FOR TypeName IN (BreakfastMeetings, BreakfastCovers,
                                            LunchSandwichMeetings,
                                            LunchSandwichCovers,
                                            LunchCookedMeetings,
                                            LunchCookedCovers)
) AS PivotTable
ORDER BY TheDate