1： 行转列
子查询，获取一定数据集结果
```
SELECT objid,action,count(1) AS [count] FROM T_MyAttention WHERE objid IN
(SELECT TOP 10 objid FROM T_MyAttention tma GROUP BY objid ORDER BY count(1) DESC)
GROUP BY objid,action
```
下面用 行转列语法获取 最终结果
```
select *
from
(
SELECT objid,action,count(1) AS [count] FROM T_MyAttention WHERE objid IN
(SELECT TOP 10 objid FROM T_MyAttention tma GROUP BY objid ORDER BY count(1) DESC)
GROUP BY objid,action
) t
pivot ( sum(count) for t.action in ([1],[2],[3],[4])) as ourpivot
```
ps:挺好挺使用的功能，微软为啥子不内置在SQLserver里呢，ms，唉！
微软官方的图：
