如何使用CASE语句在SQL Server中创建透视查询？

Question

Col1仅包含X和Y.

Col1    Col2

X       abc

Y       pqr

X       pqr

X       mnq

Y       cxr

我想这样做:

X    Y    Col2

Yes  Yes  pqr
Yes  No   abc
Yes  No   mnq
No   Yes  cxr

我应该写什么SQL查询？

Answer 1

使用SQL PIVOT运算符的解决方案:

SELECT Col2, 
  case when X=0 then 'No' else 'Yes' end as X, 
  case when Y=0 then 'No' else 'Yes' end as Y
FROM MyTable
PIVOT (
  count(Col1)
  FOR Col1 IN ([X], [Y])
) AS PivotTable;

运行样本:http://www.sqlfiddle.com/#!3/586d/14