Question

我在T-SQL中有这个存储过程，用于将DATETIME拆分为轮班。

我会将DATETIME START和DATETIME END划分为轮班（例如，每隔15分钟一班或一班）。我应该转换到临时表，以便在另一个查询中使用它。

所以为此我创造了这个循环：

BEGIN
      SET @DATASTART = '2014-11-28 06:00:00'
      SET @DATAEND = '2014-11-28 21:00:00'
    --DICHIARO DUE VARIABILI DATA CHE UTILIZZO
    --PER MANTENERE I DUE SHIFT
    DECLARE @DataFirstShift as DATETIME
    DECLARE @DataLastShift as DATETIME
    --DICHIARO UN CONTATORE PER POPOLARE IL CAMPO ID
    DECLARE @Contatore as INT
    SET @Contatore = 0
    --SETTO LA DATA FIRSTSHIFT A DATASTART
    SET @DataFirstShift = @DATA_START

    WHILE(@DataFirstShift <= @DATA_END)
        BEGIN
            --POPOLO LA DATA LAST CON UN ORA IN PIU RISPETTO ALLA PRIMA DATA
            IF @Shift LIKE 'All'
                BEGIN 
                    SET @DataLastShift = DATEADD(HOUR,1,@DataFirstShift)
                END
            ELSE 
                BEGIN 
                    SET @DataLastShift = DATEADD(MINUTE,15,@DataFirstShift)
                END
            INSERT INTO @TemporaryTable2 (ID,DATASTART,DATAEND)
            VALUES (@Contatore,@DataFirstShift,@DataLastShift)
            SET @DataFirstShift=@DataLastShift
            --INCREMENTO IL CONTATORE
            SET @Contatore+=1
        END
END

这种方法有效但我这个周期很慢。我想知道是否存在比它更快的方法。

有人能帮助我吗？此致

Answer 1

尝试以下：

--param of SP
DECLARE @DATASTART DATETIME = '2014-11-28 06:00:00'
DECLARE @DATAEND DATETIME = '2014-11-28 21:00:00'
DECLARE @Shift VARCHAR(50) = 'All'

--body
DECLARE @TemporaryTable2 TABLE
  (
     id        INT,
     startdate DATETIME,
     enddate   DATETIME
  )

DECLARE @id INT = 0

IF @Shift LIKE 'All'
BEGIN
    INSERT INTO @TemporaryTable2
    SELECT N.number + 1 AS id,
           startdate,
           enddate
    FROM   master..spt_values N
           CROSS apply (SELECT Dateadd(dd, N.number, @DATASTART),
                               Dateadd(dd, N.number + 1, @DATASTART)) AS D(startdate, enddate)
    WHERE  N.number BETWEEN 0 AND Datediff(dd, @DATASTART, @DATAEND)
           AND N.type = 'P'
END
ELSE
BEGIN
    INSERT INTO @TemporaryTable2
    SELECT N.number + 1 AS id,
           startdate,
           enddate
    FROM   master..spt_values N
           CROSS apply (SELECT Dateadd(MINUTE, N.number * 15, @DATASTART),
                               Dateadd(MINUTE, ( N.number + 1 ) * 15, @DATASTART)) AS D(startdate, enddate)
    WHERE  N.number BETWEEN 0 AND ( Datediff(MINUTE, @DATASTART, @DATAEND) / 15 )
           AND N.type = 'P'
END

SELECT *
FROM   @TemporaryTable2

存在类似的问题here。对于spt_values，此方法的唯一限制是type = 'p'范围为0到2047。因此它可以返回最多2047行。

如何优化存储过程中的循环[T-SQL]

1 个答案: