是的，您可以对表中的多个列使用多个case语句。但从您的查询中，我可以看到额外的end语句，因此刚刚将它们从您的查询中删除，并更新了last case语句。不确定这是你想要的-

SELECT description_arab, 
   cts_trx_type, 
   comp_code, 
   branch_code, 
   currency_code, 
   gl_code, 
   cif_sub_no, 
   cts_trs_no, 
   trans_date, 
   value_date, 
   fc_amount, 
   cv_amount, 
   description, 
   CASE 
          WHEN fc_amount IS NULL THEN '0' 
          ELSE fc_amount 
   END AS fc , 
   CASE 
          WHEN cts_trx_type IS NULL THEN 'JV' 
          ELSE cts_trx_type 
   END AS trx_type, 
   CASE 
       WHEN currency_code = 368 THEN 'IQD' 
       WHEN currency_code = 840 THEN 'USD' 
       ELSE 'INVALID CURRECY' -- added this to check other checks as well
      END as currency 
    FROM   dof 
          WHERE  to_date(trans_date,'DD/MM/YYYY') BETWEEN to_date('24/09/18,'dd/mm/yyyy') AND  TO_DATE('21/11/18'     ,'dd/mm/yyyy') and currency_code IS NOT NULL   order by   cts_trs_no