SQL Oracle 到 SQL Server答案

【问题标题】：SQL Oracle to SQL ServerSQL Oracle 到 SQL Server
【发布时间】：2018-07-11 12:05:21
【问题描述】：

此查询在 Oracle 中有效：

SELECT EXTRACT(YEAR FROM "DATE_OF_PUBLICATION") AS years,  
       Count("LOSS_AMOUNT_(LOCAL_CCY)") AS events,   
       Max("LOSS_AMOUNT_(LOCAL_CCY)") AS max_losses, 
       Sum("LOSS_AMOUNT_(LOCAL_CCY)") AS sum_losses 
FROM (
  select * 
  from (
     select "DATE_OF_PUBLICATION",
            "LOSS_AMOUNT_(LOCAL_CCY)" 
     FROM TEST 
     ORDER BY "LOSS_AMOUNT_(LOCAL_CCY)" DESC 
  )
) 
GROUP BY EXTRACT(YEAR FROM "DATE_OF_PUBLICATION") 
ORDER BY EXTRACT(YEAR FROM "DATE_OF_PUBLICATION")

现在，我在 SQLServer 中执行了这个查询：

SELECT DATEPART(YEAR,"DATE_OF_PUBLICATION") AS years, 
       Count("LOSS_AMOUNT_(LOCAL_CCY)") AS events,   
       Max("LOSS_AMOUNT_(LOCAL_CCY)") AS max_losses, 
       sum("LOSS_AMOUNT_(LOCAL_CCY)") AS sum_losses 
FROM (
  select * 
  from (
    select "DATE_OF_PUBLICATION",
           "LOSS_AMOUNT_(LOCAL_CCY)" 
    FROM TEST 
    ORDER BY "LOSS_AMOUNT_(LOCAL_CCY)" DESC 
  )
) 
GROUP BY DATEPART (YEAR ,"DATE_OF_PUBLICATION") 
ORDER BY DATEPART(YEAR ,"DATE_OF_PUBLICATION")

我收到此错误：

The ORDER BY clause is invalid in views, inline functions, derived tables, subqueries, and 
common table expressions, unless TOP, OFFSET or FOR XML is also specified.

【问题讨论】：

标签： sql sql-server oracle tsql

【解决方案1】：

正如错误明确指出的那样，ORDER BY 在子查询中无效。

另外：在 SQL server 中，当你使用子查询时，它必须有一个名字：

select * from ( select .....)

无效，而

select * from ( select .....) as tablename

有效

此外，您还有两个不必要的子查询级别。以下应该有效：

SELECT 
    DATEPART(YEAR , "DATE_OF_PUBLICATION") AS years, 
    Count("LOSS_AMOUNT_(LOCAL_CCY)") AS events, 
    Max("LOSS_AMOUNT_(LOCAL_CCY)") AS max_losses, 
    Sum("LOSS_AMOUNT_(LOCAL_CCY)") AS sum_losses 
FROM AAA_20180711
GROUP BY DATEPART(YEAR , "DATE_OF_PUBLICATION") 
ORDER BY DATEPART(YEAR, "DATE_OF_PUBLICATION")

【讨论】：

SELECT DATEPART(YEAR , "DATE_OF_PUBLICATION") AS 年份，Count("LOSS_AMOUNT_(LOCAL_CCY)") AS 事件，Max("LOSS_AMOUNT_(LOCAL_CCY)") AS max_losses，Sum("LOSS_AMOUNT_(LOCAL_CCY) )") AS sum_losses FROM (select * from(select "DATE_OF_PUBLICATION","LOSS_AMOUNT_(LOCAL_CCY)" FROM Test)) GROUP BY DATEPART(YEAR , "DATE_OF_PUBLICATION") ORDER BY DATEPART(YEAR, "DATE_OF_PUBLICATION")
相应地更新了答案
非常感谢，祝您有美好的一天！

【解决方案2】：

根本不需要内部的order by。虽然 Oracle 容忍它（并且可能只是忽略它），但 SQL Server 不喜欢它（这是理所当然的）。您可以将其从查询中完全删除。唯一需要的是外部order by。另外：也不需要嵌套派生表。

您可以将查询简化为：

SELECT DATEPART(YEAR,"DATE_OF_PUBLICATION") AS years, 
       Count("LOSS_AMOUNT_(LOCAL_CCY)") AS events,   
       Max("LOSS_AMOUNT_(LOCAL_CCY)") AS max_losses, 
       sum("LOSS_AMOUNT_(LOCAL_CCY)") AS sum_losses 
FROM TEST 
GROUP BY DATEPART(YEAR ,"DATE_OF_PUBLICATION") 
ORDER BY DATEPART(YEAR ,"DATE_OF_PUBLICATION")

【讨论】：

【解决方案3】：

删除Order by 子句，不要忘记在嵌套查询中添加alias，

修改后使用下一个查询：-

SELECT DATEPART(YEAR,"DATE_OF_PUBLICATION") AS years, 
       Count("LOSS_AMOUNT_(LOCAL_CCY)") AS events,   
       Max("LOSS_AMOUNT_(LOCAL_CCY)") AS max_losses, 
       sum("LOSS_AMOUNT_(LOCAL_CCY)") AS sum_losses 
FROM (
  select * 
  from (
    select "DATE_OF_PUBLICATION",
           "LOSS_AMOUNT_(LOCAL_CCY)" 
    FROM TEST 
  )t1
) t2 
GROUP BY DATEPART (YEAR ,"DATE_OF_PUBLICATION") 
ORDER BY DATEPART(YEAR ,"DATE_OF_PUBLICATION")

【讨论】：

【解决方案4】：

如果你使用，你也可以保持顺序

SELECT TOP 100 PERCENT * FROM ...

在您的子查询中。

然而，“错误”指出一般情况下，子查询不应该需要 ORDER BY 子句。考虑一下为什么你觉得你需要 ORDER BY，你可能可以安全地删除它

【讨论】：