Teradata returning Division by Zero Error - How to Adress?

Question

The following query utilizes a case statement with some division. However, it is getting snagged on a division by zero error. Any ideas on how to handle the error exception would be greatly appreciated!

CASE 
    WHEN Channel = 'DA' THEN  CAST (CASE_QTY AS DECIMAL(38,0))/SUM(CAST(CASE_QTY AS DECIMAL(38,2))) OVER (PARTITION BY ld.LOAD_ID) 
    WHEN Channel = 'SS' THEN  CAST (CASE_QTY AS DECIMAL(38,0))/SUM(CAST(CASE_QTY AS DECIMAL(38,2))) OVER (PARTITION BY ld.LOAD_ID) 
    WHEN Channel = 'XDOCK' THEN  CAST (CASE_QTY AS DECIMAL(38,0))/SUM(CAST(CASE_QTY AS DECIMAL(38,2))) OVER (PARTITION BY ld.LOAD_ID)
    WHEN Channel = '?' THEN  CAST (CASE_QTY AS DECIMAL(38,0))/SUM(CAST(CASE_QTY AS DECIMAL(38,2))) OVER (PARTITION BY ld.LOAD_ID) 
    ELSE 0
    END AS Percentage

Answer 1

Simply use NULLIF. Additionally you can simplify your query to:

CASE 
    WHEN Channel IN ('DA','SS','XDOCK','?') 
      THEN Cast(CASE_QTY AS DECIMAL(38,0))/NullIf(Sum(Cast(CASE_QTY AS DECIMAL(38,2))) Over (PARTITION BY ld.LOAD_ID),0) 
    ELSE 0
END AS Percentage