如何编写存储过程来做到这一点？

Question

我想创建一个存储过程，该存储过程接受用逗号分隔的字符串，例如“ 1,2,3,4”，并将其分解并使用这些数字在不同的表上运行查询。

所以在同一个存储过程中，它会做类似的事情

select somefield from sometable where somefield = 1
select somefield from sometable where somefield = 2
select somefield from sometable where somefield = 3
select somefield from sometable where somefield = 4

谢谢！

Answer 1

查阅Erland Sommarskog的出色文章，主题是如何将值列表传递给SQL Server 2005中的存储过程：

SQL Server 2005及更高版本中的数组和列表

由此，您应该能够根据所具有的条件来创建查询。

Answer 2

假设您要执行此操作，请参见http://www.sommarskog.se/arrays-in-sql-2005.html#CSV

select somefield from sometable where somefield in(1,2,3,4)

Answer 3

有一个非常漂亮的例子在这里 。

使用链接中定义的拆分功能，您可以执行此操作。

SELECT *
FROM table
WHERE id in ( SELECT convert(int,Value) FROM dbo.Split(@list_string,',')

或者，您可以使用表值函数split的表形式加入主查询。

Answer 4

如果您想变得复杂，可以将输入字符串转换为临时表/表变量，然后在闲暇时执行一系列IF语句或查询。

SQLServer proc以逗号分隔的输入字符串并将其作为表变量返回。

IF EXISTS(SELECT name FROM sysobjects WHERE name = 'fn_parseString' AND (type = 'TF' OR type = 'IF' OR type = 'FN'))
     DROP FUNCTION fn_parseString
GO

/* This function takes a comma delimited string of information and parses it based on commas, returning the resultant strings.  */

CREATE FUNCTION fn_parseString
(@StringToParse TEXT)
RETURNS @StringTable TABLE (ParsedString VARCHAR(8000), StringIndex INT)
AS

BEGIN

DECLARE @CurrentString VARCHAR(8000)
DECLARE @CurrentStringIndex INT
DECLARE @TextLength INT
DECLARE @Index INT
DECLARE @Letter VARCHAR(1)
DECLARE @PreviousLetter VARCHAR(1)

SET @CurrentString = ''
SET @CurrentStringIndex = 0
SET @TextLength = DATALENGTH(@StringToParse)
SET @PreviousLetter = ''

SET @Index = 1
WHILE @Index <= @TextLength
   BEGIN
    SET @Letter = SUBSTRING(@StringToParse, @Index, 1)

    IF @Letter = ','
       BEGIN
        SET @CurrentStringIndex = @CurrentStringIndex + 1

        INSERT INTO @StringTable
            (ParsedString,
             StringIndex)
        VALUES  (@CurrentString,
             @CurrentStringIndex)

        IF @@ERROR <> 0
           BEGIN
            DELETE
            FROM    @StringTable

            RETURN
           END

        SET @CurrentString = ''
       END
    ELSE IF @PreviousLetter <> ',' OR (@PreviousLetter = ',' AND @Letter <> ' ')    /* Get rid of the spaces inserted when the string was created. */
       BEGIN
        SET @CurrentString = @CurrentString + @Letter
       END

    SET @PreviousLetter = @Letter

    SET @Index = @Index + 1
   END

IF @CurrentString <> ''
   BEGIN
    SET @CurrentStringIndex = @CurrentStringIndex + 1

    INSERT INTO @StringTable
        (ParsedString,
         StringIndex)
    VALUES  (@CurrentString,
         @CurrentStringIndex)

    IF @@ERROR <> 0
       BEGIN
        DELETE
        FROM    @StringTable

        RETURN
       END
   END

RETURN

END

在其他地方访问该函数的代码：

DECLARE @CommaDelimitedString VARCHAR(8000)
SET @CommaDelimitedString = '1,2,3,4,5,6,7,8,cow,dog,horse'

DECLARE @StringTable TABLE
(StringValue VARCHAR(8000),
 ColumnID INT)

SET NOCOUNT ON

INSERT INTO @StringTable
       (StringValue,
    ColumnID)
SELECT  ParsedString,
    StringIndex
FROM    dbo.fn_ParseString(@CommaDelimitedString)

IF @@ERROR <> 0
   BEGIN
    SET NOCOUNT OFF
    RAISERROR('An error occurred while parsing the AccountIDs out of the string.',16,1) 
   END


SELECT * FROM [Sometable] JOIN  @StringTable AS tmp ON [sometable.value] = tmp.StringValue