oracle 中的 No_Data_found 异常答案

【问题标题】：No_Data_found exception in oracleoracle 中的 No_Data_found 异常
【发布时间】：2019-10-13 19:56:19
【问题描述】：

我有两个数据库表（account 和 account1）。我想输入一个帐号并首先检查是否帐号是否在帐户表中。如果它不在帐户表中，则引发异常并检查 account1 表。代码适用于此。但是如果我想在 account1 表中也找不到帐号时显示错误消息，那么我该怎么办。这是我的部分代码-

BEGIN
begin
select Balance,Cid
    into cur_balance,cl_id
    from Account 
    where Accno = x;
    select max(Tid) into id from(select Tid from trnsaction union select Tid from trnsaction1);
    id:=id+1;
    ac_branch := 'mirpur';
exception
    when no_data_found then
    select Balance,Cid
    into cur_balance,cl_id
    from account1
    where accno = x;

    select max(Tid) into id from(select Tid from trnsaction union select Tid from trnsaction1);
    id:=id+1;

    ac_branch := 'gulshan';         

end;

【问题讨论】：

标签： oracle exception plsql

【解决方案1】：

你可以使用

raise_application_error(-20001,'None of the tables contain this account !'); 或

dbms_output.put_line('None of the tables contain this account !');

在Account 表的最后一个引发异常语句中：

DECLARE
  cur_balance  Account.Balance%type;
  cl_id        Account.Cid%type;
  id           trnsaction.Tid%type;
BEGIN
  begin
        select Balance, Cid
          into cur_balance, cl_id
          from Account
         where Accno = x;

        ac_branch := 'mirpur';
    exception
      when no_data_found then
        select Balance, Cid
          into cur_balance, cl_id
          from Account1
         where accno = x;

      ac_branch := 'gulshan'; 

        exception
          when no_data_found then 
            raise_application_error(-20001,'None of the tables contain this account !');           
  end;     

  begin
      select max(Tid)
        into id
        from (select Tid
                from trnsaction
              union
              select Tid from trnsaction1);
      id := id + 1;

     exception
       when no_data_found then null;           
  end;    
END;

Account 与 Account1 的列类型以及 trnsaction1 与 trnsaction 表的列类型被认为是相对相同的。

如果您更喜欢使用dbms_output.put_line，请在它之前发出命令set serveroutput on。

顺便说一句，无需重复独立于我们感兴趣的查询的其他查询。

【讨论】：

【解决方案2】：

为什么不union all 和row_number？

begin
Select Balance,Cid, branch
into cur_balance,cl_id, ac_branch
from
(Select Balance,Cid, branch
       row_number() 
       Over (order by seq) as rn
From   
(select Balance,Cid, 1 as seq, 'mirpur' as branch
    from Account 
    where Accno = x
Union all
select Balance,Cid, 2 as seq, 'gulshan' as branch
    from account1
    where accno = x))
Where rn = 1;
    select max(Tid) into id from(select Tid from trnsaction union select Tid from trnsaction1);
    id:=id+1;
exception
    when no_data_found then
    Null; -- or dbms_output.put_line('acct not found');
end;
/

干杯！！

【讨论】：