带有Over（）的SQL轮数

Question

我有一个非常基本的SQL查询查询，它正在对从分组结果集返回的记录总数进行计算。

 SELECT   vco.OutcomeName,
          vco.VersionCompareOutcomeID,
          COUNT(t.OutcomeName) AS Total,
          ROUND(COUNT(*) * 100.0 / sum(count(*)), 1) over() AS Percentage
FROM map.VersionCompareOutcome AS vco
LEFT JOIN @temp AS t
ON vco.VersionCompareOutcomeID = t.VersionCompareOutcomeID
GROUP BY vco.OutcomeName, vco.VersionCompareOutcomeID

当我尝试使用round函数时，我收到以下错误：The function 'ROUND' is not a valid windowing function, and cannot be used with the OVER clause.

如果没有round功能，我会得到百分比，但不像我想要的那样四舍五入。

我想要的结果是2位小数：例如87.95%。

Answer 1

您不能将ROUND与OVER一起使用，只能使用聚合，排名和分析功能。

但是，您可以在子查询或CTE中进行聚合，然后在外部查询中进行舍入：

WITH CTE
AS
(

    SELECT   vco.OutcomeName,
              vco.VersionCompareOutcomeID,
              COUNT(t.OutcomeName) AS Total
    FROM map.VersionCompareOutcome AS vco
    LEFT JOIN @temp AS t ON vco.VersionCompareOutcomeID = t.VersionCompareOutcomeID
    GROUP BY vco.OutcomeName, vco.VersionCompareOutcomeID
)
SELECT
  OutcomeName,
  VersionCompareOutcomeID,
  Total,
  CASE WHEN (SELECT COUNT(*) FROM @temp) = 0 THEN 0 ELSE ROUND(Total * 100.0 / (SELECT COUNT(*) FROM @temp), 1) END AS Percentage
FROM CTE