在 SQL 服务器查询中有条件地应用多个计数

Question

我有一个 task table，其中包含一些 DateTime 类型的列，例如已完成、未决、异常。它加入 user table 我想带
userName, AllTaskCount, AllPendingTaskCount, AllCompletedTaskCount, AllExceptionTaskCount.

如果 Completed 列有值，则它将被视为已完成的任务，而如果 completed 列为空且 exception 列中有值，则它是 ExceptionTask，如果两者都不是 Completed 列没有值 exception 比它是未决任务。

所以我想在上述给定条件下有条件地应用多次计数。请帮忙...

Answer 1

您可以使用CTEs得到结果。

WITH Result AS(
    SELECT *, COUNT(1) OVER (ORDER BY Id) AS AllTasksCount
     FROM User U
    JOIN TASK T ON U.Id = T.UserId
),PendingTasks AS (
    SELECT [NAme], COUNT(1) AS AllPendingTaskCount FROM Result
    WHERE Completed IS NULL and Exception IS NULL
    GROUP BY [Name]
),CompletedTasks AS (
    SELECT [NAme], COUNT(1) AS AllCompletedTaskCount FROM Result
    WHERE Completed IS NOT NULL and Exception IS NULL
    GROUP BY [Name]
),ExceptionTasks AS (
    SELECT [NAme], COUNT(1) AS AllExecptionTaskCount FROM Result
    WHERE Completed IS NULL and Exception IS NOT NULL
    GROUP BY [Name]
)
SELECT DISTINCT R.[Name]
      ,AllTasksCount
      ,AllPendingTaskCount
      ,AllCompletedTaskCount
      ,AllExecptionTaskCount
FROM Result R
JOIN PendingTasks PT 
  ON PT.[Name] = R.[Name]
JOIN CompletedTasks CT 
  ON CT.[Name] = R.[Name]
JOIN ExceptionTasks ET 
  ON ET.[Name] = R.[Name]

添加了示例架构和数据。请根据您的要求更新它。 SQLFiddle

在 SQL 服务器查询中有条件地应用多个计数

Apply multiple count conditionally in SQL Server query

sql

sql-server

sql-server-2008

sql-server-2008-r2