牛逼SQL如果再列上存在（如果有的話則值X（

Question

我需要執行下面的邏輯子句：

如果列存在，並且具有一定的價值，然後做一些 如果沒有，那麼做一些事情。否則

IF EXISTS(
    SELECT * 
    FROM sys.columns 
    WHERE Name  = N'legacyoptions' 
     AND Object_ID = Object_ID(N'config ')) 
BEGIN 
    if (select legacyoptions from config)=1 
     begin 
      Do stuff when legacy=1 
     end 
     else begin 
      Do stuff when legacy !=1 
     END 
else 
begin 
    do stuff when legacy is not present 
end 

然而，這並不萬一legacyoptions工作不存在

Answer 1

下面是使用TRY CATCH塊和動態SQL的方式，使下面的代碼塊將不表config和/或在數據庫中legacyoptions字段進行編譯。

BEGIN TRY 
    DECLARE @legacyoptions int; 
    EXECUTE sp_executesql N'select TOP 1 @legacyoptions=legacyoptions from config', 
          N'@legacyoptions int OUTPUT', 
          @legacyoptions OUTPUT; 
    if @legacyoptions=1 
     begin 
      -- Do stuff when legacy=1 
     end 
     ELSE 
     BEGIN 
      -- Do stuff when legacy !=1 
     END 
END TRY 
BEGIN CATCH 
    -- do stuff when legacy is not present 
END CATCH 

Answer 2

試試這個：（我猜你離開，如果結束）

IF EXISTS(
    SELECT * 
    FROM sys.columns 
    WHERE Name  = N'legacyoptions' 
     AND Object_ID = Object_ID(N'config ')) 
BEGIN 
    if (select legacyoptions from config)=1 
     begin 
      Do stuff when legacy=1 
     end 
     else begin 
      Do stuff when legacy !=1 
     END 
end 
else 
begin 
    do stuff when legacy is not present 
end 

Answer 3

這工作，但似乎愚蠢的我。

IF EXISTS(SELECT * FROM sys.columns WHERE Name = N'legacyoptions' AND Object_ID = Object_ID(N'config ')) BEGIN exec(' if (select legacyoptions from config)=1 begin print ''Config==1'' end else begin print ''Config!=1'' end ') end else begin print 'no legacy' end