NC已付款客商不能删行（银行账户），没付款客商同步删行trigger|2in1 if else|

if.. then.. else用法

create or replace trigger DELETE_CUSTBANK

  before delete on bd_custbank

  for each row

declare

  -- local variables here

  pk_bas char(20);

  cursor basjob(id char) is
  
    select pk_custbank
    
      from ncv5.bd_custbank /*目标数据库表*/
    
     where pk_custbank = id
          
       and nvl(dr, 0) = 0
       and pk_custbank not in
           (select bd_custbank.pk_custbank
              from ncv5.arap_djfb, ncv5.bd_accbank, ncv5.bd_custbank
             where bd_accbank.pk_accbank = arap_djfb.skyhzh
               and bd_accbank.pk_accbank = bd_custbank.pk_accbank);

begin

  /*判断数据是否在目标数据库存在*/

  open basjob(:old.pk_custbank);

  loop
  
    fetch basjob
    
      into pk_bas;
    /*dbms_output.put_line('pa_bas:'||pk_bas);*/
    exit when basjob%notfound;
  
  end loop;

  close basjob;

  /******************************/

  if pk_bas is not null then
  
    begin
    
      delete ncv5.bd_custbank /*目标数据库表*/
      
       where pk_custbank = :old.pk_custbank;
    
    end;
  else
    raise_application_error(-20001,
                            :old.account || '已从网银付款，不能修改或删行，请取消！');
  
  end if;
end DELETE_CUSTBANK;
重要声明：cursor中是not in 这里的是“否”，然后  if pk_bas is not null then
不能理解为“否”而需要理解“数值存在”，这样就是找到非付款客商了，then可以同步删除，否则报错