SQL-Server Unpivot/Pivot示例

Question

我正在制作一个应用程序来管理酒店预订，我需要在一年中显示每月的职位空缺率。我做了一个查询，有点解决这个问题，但我想以另一种格式呈现。

我当前的查询返回如下表（2×12）：

January|February|March|April| ..... and so on 
    20  15  18  20 ..... and so on 

，我想是这样的（12X2）：

January|20 
February|15 
March|18 
... |... 

这是我的查询：

Select 
     SUM(CASE WHEN datename(month, [CheckIn]) = 'January' or datename(month, [CheckOut]) = 'January' THEN 1 ELSE 0 END) January, 
     SUM(CASE WHEN datename(month, [CheckIn]) = 'February' or datename(month, [CheckOut]) = 'February' THEN 1 ELSE 0 END) February, 
     SUM(CASE WHEN datename(month, [CheckIn]) = 'March' or datename(month, [CheckOut]) = 'March' THEN 1 ELSE 0 END) March, 
     SUM(CASE WHEN datename(month, [CheckIn]) = 'April' or datename(month, [CheckOut]) = 'April' THEN 1 ELSE 0 END) April, 
     SUM(CASE WHEN datename(month, [CheckIn]) = 'May' or datename(month, [CheckOut]) = 'May' THEN 1 ELSE 0 END) May, 
     SUM(CASE WHEN datename(month, [CheckIn]) = 'June' or datename(month, [CheckOut]) = 'June' THEN 1 ELSE 0 END) June, 
     SUM(CASE WHEN datename(month, [CheckIn]) = 'July' or datename(month, [CheckOut]) = 'July' THEN 1 ELSE 0 END) July, 
     SUM(CASE WHEN datename(month, [CheckIn]) = 'August' or datename(month, [CheckOut]) = 'August' THEN 1 ELSE 0 END) August, 
     SUM(CASE WHEN datename(month, [CheckIn]) = 'September' or datename(month, [CheckOut]) = 'September' THEN 1 ELSE 0 END) September, 
     SUM(CASE WHEN datename(month, [CheckIn]) = 'October' or datename(month, [CheckOut]) = 'October' THEN 1 ELSE 0 END) October, 
     SUM(CASE WHEN datename(month, [CheckIn]) = 'November' or datename(month, [CheckOut]) = 'November' THEN 1 ELSE 0 END) November, 
     SUM(CASE WHEN datename(month, [CheckIn]) = 'December' or datename(month, [CheckOut]) = 'December' THEN 1 ELSE 0 END) December 
FROM {Booking} INNER JOIN {Status} ON {Booking}.[StatusId] = {Status}.[Id] 
WHERE {Booking}.[CheckIn] >= @BeginDate AND {Booking}.[CheckOut] <= @EndDate AND {Status}.[Label] <> 'Canceled' 

任何帮助将不胜感激，我卡住了，并没有那么多的信息在网络上，谢谢！

Answer 1

貌似你试图做一个UNPIVOT：

SELECT Month, CheckIns 
FROM 
    (Select 
     SUM(CASE WHEN datename(month, [CheckIn]) = 'January' or datename(month, [CheckOut]) = 'January' THEN 1 ELSE 0 END) January, 
     SUM(CASE WHEN datename(month, [CheckIn]) = 'February' or datename(month, [CheckOut]) = 'February' THEN 1 ELSE 0 END) February, 
     SUM(CASE WHEN datename(month, [CheckIn]) = 'March' or datename(month, [CheckOut]) = 'March' THEN 1 ELSE 0 END) March, 
     SUM(CASE WHEN datename(month, [CheckIn]) = 'April' or datename(month, [CheckOut]) = 'April' THEN 1 ELSE 0 END) April, 
     SUM(CASE WHEN datename(month, [CheckIn]) = 'May' or datename(month, [CheckOut]) = 'May' THEN 1 ELSE 0 END) May, 
     SUM(CASE WHEN datename(month, [CheckIn]) = 'June' or datename(month, [CheckOut]) = 'June' THEN 1 ELSE 0 END) June, 
     SUM(CASE WHEN datename(month, [CheckIn]) = 'July' or datename(month, [CheckOut]) = 'July' THEN 1 ELSE 0 END) July, 
     SUM(CASE WHEN datename(month, [CheckIn]) = 'August' or datename(month, [CheckOut]) = 'August' THEN 1 ELSE 0 END) August, 
     SUM(CASE WHEN datename(month, [CheckIn]) = 'September' or datename(month, [CheckOut]) = 'September' THEN 1 ELSE 0 END) September, 
     SUM(CASE WHEN datename(month, [CheckIn]) = 'October' or datename(month, [CheckOut]) = 'October' THEN 1 ELSE 0 END) October, 
     SUM(CASE WHEN datename(month, [CheckIn]) = 'November' or datename(month, [CheckOut]) = 'November' THEN 1 ELSE 0 END) November, 
     SUM(CASE WHEN datename(month, [CheckIn]) = 'December' or datename(month, [CheckOut]) = 'December' THEN 1 ELSE 0 END) December 
    FROM {Booking} INNER JOIN {Status} ON {Booking}.[StatusId] = {Status}.[Id] 
    WHERE {Booking}.[CheckIn] >= @BeginDate AND {Booking}.[CheckOut] <= @EndDate AND {Status}.[Label] <> 'Canceled' 
) monthTotals 
UNPIVOT 
(CheckIns FOR Month IN 
    (January, February, March, April, May, June, July, August, September, October, November, December) 
) AS upvt 

Here's a simplified SQLFiddle of this

而且here's a doc page上PIVOT和UNPIVOT

Answer 2

你可以让你的case语句有点短/简单所以它的更容易阅读。 MONTH（）是一个更容易阅读功能，摆脱否则将意味着，如果它只是返回一个空其SUM（）像对待一个0

SELECT [Month], CheckIns 
FROM 
    (
    Select 
     SUM(CASE WHEN MONTH([CheckIn]) = 01 or MONTH([CheckOut]) = 01 THEN 1 END) January, 
     SUM(CASE WHEN MONTH([CheckIn]) = 02 or MONTH([CheckOut]) = 02 THEN 1 END) February, 
     SUM(CASE WHEN MONTH([CheckIn]) = 03 or MONTH([CheckOut]) = 03 THEN 1 END) March, 
     SUM(CASE WHEN MONTH([CheckIn]) = 04 or MONTH([CheckOut]) = 04 THEN 1 END) April, 
     SUM(CASE WHEN MONTH([CheckIn]) = 05 or MONTH([CheckOut]) = 05 THEN 1 END) May, 
     SUM(CASE WHEN MONTH([CheckIn]) = 06 or MONTH([CheckOut]) = 06 THEN 1 END) June, 
     SUM(CASE WHEN MONTH([CheckIn]) = 07 or MONTH([CheckOut]) = 07 THEN 1 END) July, 
     SUM(CASE WHEN MONTH([CheckIn]) = 08 or MONTH([CheckOut]) = 08 THEN 1 END) August, 
     SUM(CASE WHEN MONTH([CheckIn]) = 09 or MONTH([CheckOut]) = 09 THEN 1 END) September, 
     SUM(CASE WHEN MONTH([CheckIn]) = 10 or MONTH([CheckOut]) = 10 THEN 1 END) October, 
     SUM(CASE WHEN MONTH([CheckIn]) = 11 or MONTH([CheckOut]) = 11 THEN 1 END) November, 
     SUM(CASE WHEN MONTH([CheckIn]) = 12 or MONTH([CheckOut]) = 12 THEN 1 END) December 
    FROM [Booking] 

    INNER JOIN {Status} ON {Booking}.[StatusId] = {Status}.[Id] 
    WHERE {Booking}.[CheckIn] >= @BeginDate AND {Booking}.[CheckOut] <= @EndDate AND {Status}.[Label] <> 'Canceled' 
) MONTHTotals 
UNPIVOT 
(
CheckIns FOR [Month] IN 
    (January, February, March, April, May, June, July, August, September, October, November, December) 
) AS upvt