SQL 条件 Where 语句？答案

【问题标题】：SQL Conditional Where statement?SQL 条件 Where 语句？
【发布时间】：2013-03-08 21:05:20
【问题描述】：

我在一家医院集团工作，我们有多个站点服务器，分为大约 6 个区域。我正在 SCCM 中编写一个 sql 查询，并想用站点解析区域，这被证明是一个挑战......我想根据我正在查询的区域做一个选择性的 where 语句，但我不确定如果可以的话。我知道下面的代码被破坏了......特别是 where 行附近的 case 语句。在这种情况下可以使用类似的东西吗？

DECLARE @test AS varchar(4) = 'WBR';
SELECT 
    DISTINCT MEMB.Netbios_Name0 AS [Computer Name],
    v_GS_COMPUTER_SYSTEM.Manufacturer0 AS [Computer Manufacturer], 
    v_GS_COMPUTER_SYSTEM.Model0 AS [Computer Model], 
    v_GS_INSTALLED_SOFTWARE_CATEGORIZED.ProductName0 AS [Product Name], 
    v_GS_INSTALLED_SOFTWARE_CATEGORIZED.Publisher0 AS [Publisher],
    v_GS_INSTALLED_SOFTWARE_CATEGORIZED.SoftwareID AS [SoftwareID], 
    MEMB.SiteCode AS [Site],
    CASE MEMB.SiteCode
        When 'AB1' Then 'EBR' 
        When 'AM1' Then 'SSR'
        When 'CMB' Then 'PCR'
        When 'CO1' Then 'WBR'
        When 'CP1' Then 'WBR'
        When 'CUC' Then 'PCR'
        When 'DM1' Then 'EBR'
        When 'EM1' Then 'EBR'
        When 'LS1' Then 'WBR'
        When 'MM1' Then 'CVR'
        When 'MM2' Then 'CVR'
        When 'MP1' Then 'PCR'
        When 'MP2' Then 'PCR'
        When 'NM1' Then 'SSR'
        When 'NV1' Then 'WBR'
        When 'PA1' Then 'PCR'
        When 'PAF' Then 'PCR'
        When 'PDU' Then 'PCR'
        When 'PLA' Then 'PCR'
        When 'PMF' Then 'PCR'
        When 'PMO' Then 'PCR'
        When 'PMP' Then 'PCR'
        When 'POR' Then 'PCR'
        When 'PPV' Then 'PCR'
        When 'PRS' Then 'PCR'
        When 'PSA' Then 'PCR'
        When 'SC1' Then 'CCS'
        When 'SF1' Then 'SSR'
        When 'SG1' Then 'SSR'
        When 'SH1' Then 'PCR'
        When 'SM1' Then 'SSR'
        When 'SR1' Then 'WBR'
        When 'SS1' Then 'CCS'
        When 'SZ1' Then 'PCR'
        When 'SZ2' Then 'PCR'
        When 'VN1' Then 'SCH'
        else 'Unknown'
    end 'Region',
    v_GS_COMPUTER_SYSTEM.UserName0 AS [Last User]

    FROM v_GS_INSTALLED_SOFTWARE_CATEGORIZED 
    INNER JOIN 
    ( 
        select 
            distinct v_R_System_Valid.ResourceID, 
            v_FullCollectionMembership.SiteCode,
            v_R_System_Valid.Netbios_Name0 

            from v_R_System_Valid 
            INNER JOIN v_FullCollectionMembership ON    v_FullCollectionMembership.ResourceID = v_R_System_Valid.ResourceID 

            case @test
                when 'SCAH' Then (where v_FullCollectionMembership.SiteCode='VN1')
                when 'CCS' Then (where v_FullCollectionMembership.SiteCode='SS1' OR v_FullCollectionMembership.SiteCode='SC1' )
                when 'CVR' Then (where v_FullCollectionMembership.SiteCode='MM1' OR v_FullCollectionMembership.SiteCode='MM2')
                when 'EBR' Then (where v_FullCollectionMembership.SiteCode='AB1' OR v_FullCollectionMembership.SiteCode='DM1' OR v_FullCollectionMembership.SiteCode='EM1')
                when 'PCR' Then (where v_FullCollectionMembership.SiteCode='CMB' OR v_FullCollectionMembership.SiteCode='CUC' OR v_FullCollectionMembership.SiteCode='MP1' OR v_FullCollectionMembership.SiteCode='MP2' OR v_FullCollectionMembership.SiteCode='PA1' OR v_FullCollectionMembership.SiteCode='PAF' OR v_FullCollectionMembership.SiteCode='PDU' OR v_FullCollectionMembership.SiteCode='PLA' OR v_FullCollectionMembership.SiteCode='PMF' OR v_FullCollectionMembership.SiteCode='PMO' OR v_FullCollectionMembership.SiteCode='PMP' OR v_FullCollectionMembership.SiteCode='POR' OR v_FullCollectionMembership.SiteCode='PPV' OR v_FullCollectionMembership.SiteCode='PRS' OR v_FullCollectionMembership.SiteCode='PSA' OR v_FullCollectionMembership.SiteCode='SH1' OR v_FullCollectionMembership.SiteCode='SZ1' OR v_FullCollectionMembership.SiteCode='SZ2')
                when 'SSR' Then (where v_FullCollectionMembership.SiteCode='AM1' OR v_FullCollectionMembership.SiteCode='NM1' OR v_FullCollectionMembership.SiteCode='SF1' OR v_FullCollectionMembership.SiteCode='SG1' OR v_FullCollectionMembership.SiteCode='SM1')
                when 'WBR' Then (where v_FullCollectionMembership.SiteCode='CO1' OR v_FullCollectionMembership.SiteCode='CP1' OR v_FullCollectionMembership.SiteCode='LS1' OR v_FullCollectionMembership.SiteCode='NV1' OR v_FullCollectionMembership.SiteCode='SR1')
            end
            --SCAH
            --where v_FullCollectionMembership.SiteCode='VN1'
            --CCS
            --where v_FullCollectionMembership.SiteCode='SS1' OR v_FullCollectionMembership.SiteCode='SC1' 
            --CVR
            --where v_FullCollectionMembership.SiteCode='MM1' OR v_FullCollectionMembership.SiteCode='MM2'
            --EBR
            --where v_FullCollectionMembership.SiteCode='AB1' OR v_FullCollectionMembership.SiteCode='DM1' OR v_FullCollectionMembership.SiteCode='EM1'
            --PCR
            --where v_FullCollectionMembership.SiteCode='CMB' OR v_FullCollectionMembership.SiteCode='CUC' OR v_FullCollectionMembership.SiteCode='MP1' OR v_FullCollectionMembership.SiteCode='MP2' OR v_FullCollectionMembership.SiteCode='PA1' OR v_FullCollectionMembership.SiteCode='PAF' OR v_FullCollectionMembership.SiteCode='PDU' OR v_FullCollectionMembership.SiteCode='PLA' OR v_FullCollectionMembership.SiteCode='PMF' OR v_FullCollectionMembership.SiteCode='PMO' OR v_FullCollectionMembership.SiteCode='PMP' OR v_FullCollectionMembership.SiteCode='POR' OR v_FullCollectionMembership.SiteCode='PPV' OR v_FullCollectionMembership.SiteCode='PRS' OR v_FullCollectionMembership.SiteCode='PSA' OR v_FullCollectionMembership.SiteCode='SH1' OR v_FullCollectionMembership.SiteCode='SZ1' OR v_FullCollectionMembership.SiteCode='SZ2'
            --SSR
            --where v_FullCollectionMembership.SiteCode='AM1' OR v_FullCollectionMembership.SiteCode='NM1' OR v_FullCollectionMembership.SiteCode='SF1' OR v_FullCollectionMembership.SiteCode='SG1' OR v_FullCollectionMembership.SiteCode='SM1'
            --WBR
            --where v_FullCollectionMembership.SiteCode='CO1' OR v_FullCollectionMembership.SiteCode='CP1' OR v_FullCollectionMembership.SiteCode='LS1' OR v_FullCollectionMembership.SiteCode='NV1' OR v_FullCollectionMembership.SiteCode='SR1'
    ) MEMB on MEMB.ResourceID = v_GS_INSTALLED_SOFTWARE_CATEGORIZED.ResourceID 
    INNER JOIN v_GS_COMPUTER_SYSTEM on v_GS_COMPUTER_SYSTEM.ResourceID = MEMB.ResourceID 

    where v_GS_INSTALLED_SOFTWARE_CATEGORIZED.SoftwareID = '76F63E67-3A8F-4675-9FB1-08A3E40CE9FE'
    --where v_GS_INSTALLED_SOFTWARE_CATEGORIZED.SoftwareID = @SoftwareID
    Order by MEMB.Netbios_Name0 ASC

【问题讨论】：

有了这个大小的列表，我只需将值列表放在另一个表中，并在AltTable.Code = MEMB.SiteCode 上使用左外连接查询它。然后，在您的选择中，您可以执行 COALESCE(AltTable.Value, 'Unknown')，因此如果没有返回任何内容，它将使用“未知”...

标签： sql conditional where statements

【解决方案1】：

你不能把where声明：

  (case when @test = 'SCAH' and v_FullCollectionMembership.SiteCode='VN1' then 'true'
        when @test = 'CCS' and e v_FullCollectionMembership.SiteCode in ('SS1', 'SC1') 
        . . .
  end) = 'true'

我建议将其移至where 子句，而不是尝试将其保留在on 子句中。如果它保留在on 子句中，则需要在其前面加上and（或or，具体取决于逻辑）。

【讨论】：

【解决方案2】：

如果你想做一个“选择性where”子句，你也可以使用动态sql。


declare @sql varchar(max)
set @sql = 'select * from table '
if( @regions = '??')
  set @sql = @sql + ' where ....'
else if( @regions = '???' )
  set @sql = @sql + ' where ...'
exec(@sql)

【讨论】：

好的，看起来这会起作用......而且我没有 15 个代表来支持你的评论，但我现在遇到了我的权限不允许我使用 exec 的问题。 ..我正在努力，但此时我无法完全验证我的语法。当我解决这个问题时......我会尝试的。