Question

我有一个LEAVE表如下

EMPID       LEAVEDT       APPDT      LEAVETYPE
------      -------       -------    ---------
E1          10-3-13       5-3-13      CL
E1          11-3-13       5-3-13      CL
E1          12-3-13       5-3-13      CL
E1          13-3-13       5-3-13      SL
E1          14-3-13       5-3-13      SL
E1          15-3-13       5-3-13      PL
E1          16-3-13       5-3-13      CL
E1          17-3-13       5-3-13      CL
E1          18-3-13       5-3-13      PL
E1          19-3-13       5-3-13      PL
E1          20-3-13       5-3-13      CL

现在我想要获取记录，其中我想要显示员工E1每次休假的次数和天数。对于上面的例子，我的查询结果应该是：---

EMPID      FROM      TO         LEAVETYPE
-----      -----    ------      ---------
E1         10-3-13  12-3-13     CL
E1         13-3-13  14-3-13     SL
E1         15-3-13  15-3-13     PL
E1         16-3-13  17-3-13     CL
E1         18-3-13  19-3-13     PL
E1         20-3-13  20-3-13     CL

请帮助我使用合适的SQL查询。请注意：empid和leavedt是我桌子的主键。

Answer 1

对表结构进行少量修改，如下所示。

     create table leaves (empid varchar(10) , 
                 leavefromdt date,
                 leavetodate date,
                 appdate date,
                 leavetype varchar(2));

示例数据

      insert into leaves values('E1', Cast('3-10-2013' as datetime),
        Cast('3-12-2013' as datetime), Cast('3-5-2013' as datetime),'CL');

      insert into leaves values('E1',Cast('3-13-2013'as datetime),
        Cast('3-14-2013'as datetime),Cast('5-3-2013'as datetime),'SL');

      insert into leaves values('E1',Cast('3-15-2013'as datetime),
        Cast('3-15-2013'as datetime),Cast('5-3-2013'as datetime),'PL');

      insert into leaves values('E1',Cast('3-16-2013'as datetime),
         Cast('3-17-2013'as datetime),Cast('5-3-2013'as datetime),'CL');

查询

     select * , DATEDIFF(DAY, leavefromdt,leavetodate )+1 days from leaves
      order by empid,leavetype

Demo SQLFiddle

如何根据更改列值获取记录数

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