Question

我正在使用SQL Server 2010。

我在数据库中有一个表，其中包含如下所示的记录：

Id | EmpName  | JoinDate                | ResignedDate
---+----------+-------------------------+--------------    
1  | Govind   | 2014-04-02 00:00:00.000 | 2014-04-02
2  | Aravind  | 2014-04-05 00:00:00.000 | 2014-04-05
3  | Aravind  | 2014-04-07 00:00:00.000 | 2014-04-10
4  | Aravind  | 2014-04-10 00:00:00.000 | 2014-04-11
5  | Aravind  | 2014-04-14 00:00:00.000 | 2014-04-16

现在，我希望显示两个日期（joinDate，ResignDate）和该日期之间的差异，可用的数量不同

示例输出：

DateDifferent      Count
-------------      -----
0                     2
1                     1
2                     1
3                     1

这里显示的是我的示例查询

entityManager.createNativeQuery(SELECT 
  DATEDIFF(day, e.joinedDate , e.resignedDate), 
  COUNT(DATEDIFF(day, e.joinedDate , e.resignedDate)))
FROM 
  Employee e 
GROUP BY 
  DATEDIFF(e.joinedDate , e.resignedDate) ORDER BY (DATEDIFF(e.joinedDate , e.resignedDate)));

此查询适用于mssql查询浏览器，但是当我在JPA Native Query（Java代码）中使用查询时，此查询无法正常工作

任何人帮助我......

Answer 1

SQL Fiddle

MS SQL Server 2008架构设置：

CREATE TABLE Employee
    ([Id] int, [EmpName] varchar(7), [JoinDate] datetime, [ResignedDate] datetime)
;

INSERT INTO Employee
    ([Id], [EmpName], [JoinDate], [ResignedDate])
VALUES
    (1, 'Govind', '2014-04-02 00:00:00', '2014-04-02 00:00:00'),
    (2, 'Aravind', '2014-04-05 00:00:00', '2014-04-05 00:00:00'),
    (3, 'Aravind', '2014-04-07 00:00:00', '2014-04-10 00:00:00'),
    (4, 'Aravind', '2014-04-10 00:00:00', '2014-04-11 00:00:00'),
    (5, 'Aravind', '2014-04-14 00:00:00', '2014-04-16 00:00:00')
;

查询1 ：

SELECT
      DATEDIFF(DAY, JoinDate, ResignedDate) AS DateDifferent
    , COUNT(DATEDIFF(DAY, JoinDate, ResignedDate)) as FrequencyOf
FROM Employee
GROUP BY DATEDIFF(DAY, JoinDate, ResignedDate)
ORDER BY DateDifferent

请注意！您可以在ORDER BY子句中使用列别名（例如DateDifferent）

<强> Results ：

| DateDifferent | FrequencyOf |
|---------------|-------------|
|             0 |           2 |
|             1 |           1 |
|             2 |           1 |
|             3 |           1 |

SQL Server从日期范围获得两天差异和天数

1 个答案: