如何使用别名或变量比较SQL中的值

我正在将SQLs别名设置为变量，以替换下面的excel公式

=+IF((O2+Z2)=0,0,+IF(AA2=0,(O2*-1),+IF(AND(AA2>0,(((R2*O2)/(O2+Z2))+H2)<= (O2*-1)),(O2*-1),(((R2*O2)/(O2+Z2))+H2))))

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使用

CASE

语句，如：

CASE 
  WHEN Balance = 0 THEN -- some value, or a formula
  WHEN Balance < 0 THEN -- maybe some other value, or a formula  
  ELSE -- another value, or formula
END AS Something

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安格尔。这是由一家名为ACTIAN Software的公司提供的

CASE 
  WHEN Balance = 0 THEN -- some value, or a formula
  WHEN Balance < 0 THEN -- maybe some other value, or a formula  
  ELSE -- another value, or formula
END AS Something

SELECT CASE
         WHEN Balance = 0 THEN 0
         ELSE Something / Balance
       END AS SomethingDividedByBalance
  FROM (SELECT -- huge formula ending with AS Balance
             , -- another formula AS Something
          FROM yourTables
     ) subquery