替代FIRST_VALUE

Question

我想运行此查询：

;WITH ToUpdate AS (
   SELECT Id1, Id2,
          FIRST_VALUE(Id1) OVER (PARTITION BY Id2 ORDER BY Id1) AS newValue
   FROM mytable
)
UPDATE ToUpdate
SET Id2 = newValue

但是在SQL Server 2008中没有FIRST_VALUE，还有其他选择吗？

Answer 1

试试这个：使用OUTER APPLY

;WITH ToUpdate AS (
      SELECT Id1, Id2,
      M.newValue AS newValue
      FROM mytable t1
      OUTER APPLY(
         SELECT top 1 t2.ID1 AS newValue
         FROM mytable t2 WHERE t1.Id2=t2.Id2
         ORDER BY t2.ID1
      )M   
)
UPDATE ToUpdate
SET Id2 = newValue