sql - 为每条记录选择多条记录

Question

我正在编写一条 sql 语句，用户应在其中输入“起始日期”和“截止日期”(少于 31 天) 对于每个日期，我需要从与员工相关的表中选择字段

我需要一个简单方法的逻辑。应该等一会儿吧？

我通过这个查询得到了日期列表:

DECLARE @date TABLE(d DATETIME)

DECLARE @d DATETIME
SET @d = '20090101'

WHILE @d <= '20090102' BEGIN

    INSERT INTO @date VALUES (@d)
    SET @d = @d + 1

END

SELECT d AS DateCol,  dbo.ta_DayOfWeek(d) AS Day,
DATENAME(weekday, DATEADD(day,0,d)) AS DayName FROM @date

这些是我需要为每条记录使用的一些字段:

SELECT  ta_timecard.EmpID ,
        emp.name ,
        emp.code ,
        ta_timecard.schedindate--,
FROM ta_timecard
INNER JOIN emp ON ta_timecard.empid = emp.id
WHERE ta_timecard.schedindate BETWEEN @FromDate AND @ToDate
GROUP BY ta_timecard.EmpID ,
        emp.name ,
        emp.code ,
        ta_timecard.schedindate

提前致谢。

Answer 1

试试这个 -

查询:

DECLARE 
      @DateFrom DATETIME
    , @DateTo DATETIME

SELECT 
      @DateFrom = '20130101'
    , @DateTo = '20130202'

SELECT 
      DateCol
    , [DayName] = DATENAME(WEEKDAY, DateCol)
    , [Day] = DATEPART(WEEKDAY, DateCol)
FROM (
    SELECT DateCol = DATEADD(DAY, sv.number, t.DateFrom)
    FROM (
        SELECT 
              DateFrom = @DateFrom
            , diff = DATEDIFF(DAY, @DateFrom, @DateTo)
    ) t
    JOIN [master].dbo.spt_values sv ON sv.number <= diff
    WHERE sv.[type] = 'p'
) t2

输出:

DateCol                 DayName                        Day
----------------------- ------------------------------ -----------
2013-01-01 00:00:00.000 Tuesday                        3
2013-01-02 00:00:00.000 Wednesday                      4
2013-01-03 00:00:00.000 Thursday                       5
2013-01-04 00:00:00.000 Friday                         6
2013-01-05 00:00:00.000 Saturday                       7
2013-01-06 00:00:00.000 Sunday                         1
2013-01-07 00:00:00.000 Monday                         2
2013-01-08 00:00:00.000 Tuesday                        3
....
2013-01-31 00:00:00.000 Thursday                       5
2013-02-01 00:00:00.000 Friday                         6
2013-02-02 00:00:00.000 Saturday                       7

更新(PIVOT + DYNAMIC SQL):

SET NOCOUNT ON;

DECLARE 
      @DateFrom DATETIME
    , @DateTo DATETIME

SELECT 
      @DateFrom = '20130501'
    , @DateTo = '20130515'

DECLARE @SQL_Pivot NVARCHAR(MAX)
SELECT @SQL_Pivot = STUFF((
    SELECT ', [' + 
        CONVERT(VARCHAR(8), DateCol, 1) + 
        ' ' + 
        LEFT(DATENAME(WEEKDAY, DateCol), 3) + ']'
    FROM (
        SELECT DateCol = DATEADD(DAY, sv.number, t.DateFrom)
        FROM (
            SELECT 
                  DateFrom = @DateFrom
                , diff = DATEDIFF(DAY, @DateFrom, @DateTo)
        ) t
        JOIN [master].dbo.spt_values sv ON sv.number <= diff
        WHERE sv.[type] = 'p'
    ) t
    FOR XML PATH(''), TYPE).value('.', 'NVARCHAR(MAX)'), 1, 2, '')

IF OBJECT_ID(N'tempdb.dbo.#emp') IS NOT NULL
   DROP TABLE tempdb.dbo.#emp

CREATE TABLE #emp
(
      EmpID INT PRIMARY KEY
    , Name NVARCHAR(50)
)

INSERT INTO #emp (EmpID, Name)
VALUES (1, N'Nejthe'), (2, N'DevArt')  

IF OBJECT_ID(N'tempdb.dbo.#timecard') IS NOT NULL
   DROP TABLE tempdb.dbo.#timecard

CREATE TABLE #timecard
(
      EmpID INT
    , ScheduleDate DATETIME
)

INSERT INTO #timecard (EmpID, ScheduleDate)
VALUES 
      (1, '2013-05-02 13:20:08')
    , (2, '2013-05-01 14:24:34')
    , (1, '2013-05-01 13:34:07') 
    , (1, '2013-05-05 12:20:48')  
    , (2, '2013-05-08 17:20:48') 

DECLARE @SQL NVARCHAR(MAX)
SELECT @SQL = ' 
SELECT *
FROM (
    SELECT 
          t.EmpID
        , e.Name
        , OnlyTime = CONVERT(VARCHAR(10), t.ScheduleDate, 108)
        , OnlyDate = CONVERT(VARCHAR(8), t.ScheduleDate, 1) + '' '' + LEFT(DATENAME(WEEKDAY, ScheduleDate), 3)
    FROM #timecard t
    JOIN #emp e ON t.EmpID = e.EmpID
) o
PIVOT
(
    MIN(o.OnlyTime)
    FOR o.OnlyDate IN (' + @SQL_Pivot + ')
) pt
ORDER BY EmpID'

EXEC sys.sp_executesql @SQL

输出:

EmpID  Name      05/01/13 Wed 05/02/13 Thu 05/03/13 Fri 05/04/13 Sat 05/05/13 Sun 05/06/13 Mon 05/07/13 Tue 05/08/13 Wed 05/09/13 Thu 05/10/13 Fri 05/11/13 Sat 05/12/13 Sun 05/13/13 Mon 05/14/13 Tue 05/15/13 Wed
------ --------- ------------ ------------ ------------ ------------ ------------ ------------ ------------ ------------ ------------ ------------ ------------ ------------ ------------ ------------ ------------
1      Nejthe    13:34:07     13:20:08     NULL         NULL         12:20:48     NULL         NULL         NULL         NULL         NULL         NULL         NULL         NULL         NULL         NULL
2      DevArt    14:24:34     NULL         NULL         NULL         NULL         NULL         NULL         17:20:48     NULL         NULL         NULL         NULL         NULL         NULL         NULL