如何使用枢轴来获得这个？

Question

我有张像这样的桌子

DATE        AREA 
01-01-2018   AREA-1
02-01-2018   AREA-1
03-01-2018   AREA-2

我想要的结果应该是这样的：

AREA    01-01-2018   02-01-2018   03-01-2018
AREA-1    YES           YES          NO
AREA-2    NO            NO          YES

我怎么能拿到这个？

Answer 1

这里有一种使用Pivot的方法

SELECT AREA,
       COALESCE([01-01-2018], 'NO'),
       COALESCE([02-01-2018], 'NO'),
       COALESCE([03-01-2018], 'NO')
FROM   (SELECT *,
               'YES' AS t
        FROM   Yourtable)a
       PIVOT(Max(t)
            FOR DATE IN ([01-01-2018],[02-01-2018],[03-01-2018]) ) pv 

更简单的方法

SELECT AREA,
       Max(CASE WHEN date = '01-01-2018' THEN 'YES' ELSE 'NO' END),
       Max(CASE WHEN date = '02-01-2018' THEN 'YES' ELSE 'NO' END),
       Max(CASE WHEN date = '03-01-2018' THEN 'YES' ELSE 'NO' END)
FROM   Yourtable
GROUP  BY AREA 

动态版本

DECLARE @col_list    VARCHAR(max)='',
        @select_list VARCHAR(max)='',
        @sql         VARCHAR(max)

SET @col_list = Stuff((SELECT DISTINCT ',' + Quotename(DATE)
                       FROM   Yourtable
                       FOR xml path('')), 1, 1, '')
SET @select_list = Stuff((SELECT DISTINCT ',COALESCE(' + Quotename(DATE) + ',''NO'') as ' + Quotename(DATE)
                          FROM   Yourtable
                          FOR xml path('')), 1, 1, '')
SET @sql = '
    SELECT AREA,' + @select_list + '
    FROM   (SELECT *,
                   ''YES'' AS t
            FROM   Yourtable)a
           PIVOT(Max(t)
                FOR DATE IN (' + @col_list + ') ) pv'

EXEC (@sql) 

注意:始终以Date类型而不是varchar类型存储日期。