为什么将参数作为列名？答案

【问题标题】：Why a parameter is taken as a column name?为什么将参数作为列名？
【发布时间】：2020-07-18 21:48:12
【问题描述】：

我有这个动态查询

ALTER PROCEDURE [dbo].[GetEquipmentsAllData] 
   @Eq_IN VARCHAR(18) = ''
  ,@FromDate DATE = NULL
  ,@ToDate DATE = NULL
  ,@ServertableName VARCHAR(400)
AS
BEGIN
  IF (ISNULL(@servertableName, '') = '')
    SET @servertableName = '[Vail-PlantAdgas-Webservices]'

  DECLARE @Sql NVARCHAR(max)

  IF (@EQ_IN = '')
  BEGIN
    IF (
        @FromDate IS NULL
        AND @ToDate IS NULL
        )
    BEGIN
      SET @Sql = 'Select 
            distinct H.EQHeaderID,H.EQUNR ''Equipment No'', H.STTXT ''Description'', H.EQTYP ''Equipment Type'', 
            --H.DATAB ''Valid From'', 

            g.EQART ''Object Type'', g.HERST ''Manufacturer'', g.TYPBZ ''Model No'',  
            g.SERGE ''Manufacturer Serial No'', g.HERLD ''Manufacturer Country'', g.BAUJJ ''Construction Year'', g.BAUMM ''Construction Month'',

            loc.SWERK ''Maint Plant'', loc.STORT ''Location'', loc.BEBER ''Plant Section'',

            Org.BUKRS ''Company Code'', Org.ANLNR ''Asset'', Org.GSBER ''Business Area'', Org.KOSTL ''Cost Center'', Org.PROID ''WBS Element'',

            str.TPLNR ''Functional Location'', str.HEQNR ''Superior Equipment'', str.POSNR ''Position'', str.SUBMT ''Const Type''


            from  ' + @servertableName + '.dbo.EQ_Header h 

            left Join ' + @servertableName + '.dbo.EQ_General g
            ON h.EQHeaderID= g.HeaderID
            left Join ' + @servertableName + 
        '.dbo.EQ_Location loc
            ON loc.HeaderID= h.EQHeaderID
            left Join ' + @servertableName + '.dbo.EQ_Organizations org
            ON org.HeaderID= loc.HeaderID
            left Join ' + @servertableName + '.dbo.EQ_Structure str
            ON str.HeaderID= org.HeaderID
            --Left Join ' + @servertableName + '.dbo.Equipment eq
            --ON eq.EquipmentNo= h.EQUNR
            Where h.Status IS NULL OR Status NOT IN(1,3)'
    END
    ELSE
    BEGIN
      SET @Sql = 'Select 
            distinct H.EQHeaderID,H.EQUNR ''Equipment No'', H.STTXT ''Description'', H.EQTYP ''Equipment Type'', 
            --H.DATAB ''Valid From'', 

            g.EQART ''Object Type'', g.HERST ''Manufacturer'', g.TYPBZ ''Model No'',  
            g.SERGE ''Manufacturer Serial No'', g.HERLD ''Manufacturer Country'', g.BAUJJ ''Construction Year'', g.BAUMM ''Construction Month'',

            loc.SWERK ''Maint Plant'', loc.STORT ''Location'', loc.BEBER ''Plant Section'',

            Org.BUKRS ''Company Code'', Org.ANLNR ''Asset'', Org.GSBER ''Business Area'', Org.KOSTL ''Cost Center'', Org.PROID ''WBS Element'',

            str.TPLNR ''Functional Location'', str.HEQNR ''Superior Equipment'', str.POSNR ''Position'', str.SUBMT ''Const Type''


            from  ' + @servertableName + '.dbo.EQ_Header h 

            left Join ' + @servertableName + '.dbo.EQ_General g
            ON h.EQHeaderID= g.HeaderID
            left Join ' + @servertableName + 
        '.dbo.EQ_Location loc
            ON loc.HeaderID= h.EQHeaderID
            left Join ' + @servertableName + '.dbo.EQ_Organizations org
            ON org.HeaderID= loc.HeaderID
            left Join ' + @servertableName + '.dbo.EQ_Structure str
            ON str.HeaderID= org.HeaderID
            --Left Join ' + @servertableName + '.dbo.Equipment eq
            --ON eq.EquipmentNo= h.EQUNR

            Where h.Status IS NULL OR Status NOT IN(1,3) and
            h.EntryDateTime BETWEEN ''' + convert(NVARCHAR(20), @FromDate) + ''' AND ''' + convert(NVARCHAR(20), @ToDate) + ''''
    END
  END
  ELSE
  BEGIN
    IF (
        @FromDate IS NULL
        AND @ToDate IS NULL
        )
    BEGIN
      SET @Sql = 'Select 
            distinct H.EQHeaderID,H.EQUNR ''Equipment No'', H.STTXT ''Description'', H.EQTYP ''Equipment Type'', 
            --H.DATAB ''Valid From'', 

            g.EQART ''Object Type'', g.HERST ''Manufacturer'', g.TYPBZ ''Model No'',  
            g.SERGE ''Manufacturer Serial No'', g.HERLD ''Manufacturer Country'', g.BAUJJ ''Construction Year'', g.BAUMM ''Construction Month'',

            loc.SWERK ''Maint Plant'', loc.STORT ''Location'', loc.BEBER ''Plant Section'',

            Org.BUKRS ''Company Code'', Org.ANLNR ''Asset'', Org.GSBER ''Business Area'', Org.KOSTL ''Cost Center'', Org.PROID ''WBS Element'',

            str.TPLNR ''Functional Location'', str.HEQNR ''Superior Equipment'', str.POSNR ''Position'', str.SUBMT ''Const Type''


            from  ' + @servertableName + '.dbo.EQ_Header h 

            left Join ' + @servertableName + '.dbo.EQ_General g
            ON h.EQHeaderID= g.HeaderID
            left Join ' + @servertableName + 
        '.dbo.EQ_Location loc
            ON loc.HeaderID= h.EQHeaderID
            left Join ' + @servertableName + '.dbo.EQ_Organizations org
            ON org.HeaderID= loc.HeaderID
            left Join ' + @servertableName + '.dbo.EQ_Structure str
            ON str.HeaderID= org.HeaderID
            --Left Join ' + @servertableName + '.dbo.Equipment eq
            --ON eq.EquipmentNo= h.EQUNR
            where h.EQUNR= ' + @Eq_IN + ' and h.Status IS NULL OR Status NOT IN(1,3)'
    END
    ELSE
    BEGIN
      SET @Sql = 'Select 
            distinct H.EQHeaderID,H.EQUNR ''Equipment No'', H.STTXT ''Description'', H.EQTYP ''Equipment Type'', 
            --H.DATAB ''Valid From'', 

            g.EQART ''Object Type'', g.HERST ''Manufacturer'', g.TYPBZ ''Model No'',  
            g.SERGE ''Manufacturer Serial No'', g.HERLD ''Manufacturer Country'', g.BAUJJ ''Construction Year'', g.BAUMM ''Construction Month'',

            loc.SWERK ''Maint Plant'', loc.STORT ''Location'', loc.BEBER ''Plant Section'',

            Org.BUKRS ''Company Code'', Org.ANLNR ''Asset'', Org.GSBER ''Business Area'', Org.KOSTL ''Cost Center'', Org.PROID ''WBS Element'',

            str.TPLNR ''Functional Location'', str.HEQNR ''Superior Equipment'', str.POSNR ''Position'', str.SUBMT ''Const Type''


            from  ' + @servertableName + '.dbo.EQ_Header h 

            left Join ' + @servertableName + '.dbo.EQ_General g
            ON h.EQHeaderID= g.HeaderID
            left Join ' + @servertableName + 
        '.dbo.EQ_Location loc
            ON loc.HeaderID= h.EQHeaderID
            left Join ' + @servertableName + '.dbo.EQ_Organizations org
            ON org.HeaderID= loc.HeaderID
            left Join ' + @servertableName + '.dbo.EQ_Structure str
            ON str.HeaderID= org.HeaderID
            --Left Join ' + @servertableName + '.dbo.Equipment eq
            --ON eq.EquipmentNo= h.EQUNR
            where h.EQUNR= ' + @Eq_IN + '
            and Cast(h.EntryDateTime as Date) BETWEEN ''' + convert(NVARCHAR(20), @FromDate) + ''' AND ''' + convert(NVARCHAR(20), @ToDate) + '''
            and h.Status IS NULL OR Status NOT IN(1,3)'
    END
  END

  --Exec(@Sql)
  PRINT (@Sql)
END

打印出来是这样的：

Select 
    distinct H.EQHeaderID,H.EQUNR 'Equipment No', H.STTXT 'Description', H.EQTYP 'Equipment Type', 
    --H.DATAB 'Valid From', 

    g.EQART 'Object Type', g.HERST 'Manufacturer', g.TYPBZ 'Model No',  
    g.SERGE 'Manufacturer Serial No', g.HERLD 'Manufacturer Country', g.BAUJJ 'Construction Year', g.BAUMM 'Construction Month',

    loc.SWERK 'Maint Plant', loc.STORT 'Location', loc.BEBER 'Plant Section',

    Org.BUKRS 'Company Code', Org.ANLNR 'Asset', Org.GSBER 'Business Area', Org.KOSTL 'Cost Center', Org.PROID 'WBS Element',

    str.TPLNR 'Functional Location', str.HEQNR 'Superior Equipment', str.POSNR 'Position', str.SUBMT 'Const Type'


    from  [Vail-PlantAdgas-Webservices].dbo.EQ_Header h 

    left Join [Vail-PlantAdgas-Webservices].dbo.EQ_General g
    ON h.EQHeaderID= g.HeaderID
    left Join [Vail-PlantAdgas-Webservices].dbo.EQ_Location loc
    ON loc.HeaderID= h.EQHeaderID
    left Join [Vail-PlantAdgas-Webservices].dbo.EQ_Organizations org
    ON org.HeaderID= loc.HeaderID
    left Join [Vail-PlantAdgas-Webservices].dbo.EQ_Structure str
    ON str.HeaderID= org.HeaderID
    --Left Join [Vail-PlantAdgas-Webservices].dbo.Equipment eq
    --ON eq.EquipmentNo= h.EQUNR
    where h.EQUNR= eq01
    and Cast(h.EntryDateTime as Date) BETWEEN '2014-01-01' AND '2020-01-01'
    and h.Status IS NULL OR Status NOT IN(1,3)

当我向它传递参数时它会抛出错误：

错误：列名“eq01”无效。

参数：'eq01','2014-01-01','2020-01-01',''

现在我尝试了很多方法来解决它，但不知道我错过了什么。

【问题讨论】：

请提供一些示例数据。预期的输入/输出。
为什么@Eq_IN不在字符串引号内？

标签： sql sql-server tsql stored-procedures sql-server-2012

【解决方案1】：

您的代码中有两个该子句的实例：

  where h.EQUNR= ' + @Eq_IN + '

参数被定义为VARCHAR(18)，所以当你在动态SQL中引用它时，你需要设置它，以便在评估语句时将值包裹在单引号中。您可以通过在动态查询中将其用双单引号括起来来做到这一点。第一个单引号是第二个单引号的转义字符。

那么上面的实例应该是什么：

  where h.EQUNR= ''' + @Eq_IN + '''

没有这些引号，文本将按照您发布的方式进行评估，其中eq01 被视为列名，而不是文本值。

【讨论】：