抑制 ORA-01403: 未找到数据异常

Question

我有以下代码

SELECT SUM(nvl(book_value,
                   0))
    INTO v_balance
    FROM account_details
    WHERE currency = 'UGX';

--Write the balance away

SELECT SUM(nvl(book_value,
                   0))
    INTO v_balance
    FROM account_details
    WHERE currency = 'USD';

--Write the balance away

现在的问题是，表格中可能没有该特定货币的数据，但可能有“美元”货币的数据。所以基本上我想将总和选择到我的变量中，如果没有数据，我希望我的存储过程继续并且不抛出 01403 异常。

我也不想将每个 select 放入 BEGIN EXCEPTION END 块中的语句中，所以有什么方法可以抑制异常并将 v_balance 变量保持在未定义（NULL）状态而不需要异常块？

Answer 1

select nvl(balance,0) 
into v_balance
from 
(
    select sum(nvl(book_value,0)) as balance
    from account_details
    where currency = 'UGX'
);

Answer 2

SELECT L1.PKCODE L1CD,  L1.NAME L1N, L1.LVL L1LVL,
          L2.PKCODE L2CD, L2.NAME L2N,  L2.LVL L2LVL,
          L5.PKCODE L5CD, L5.NAME L5N,

INFOTBLM.OPBAL (  L5.PKCODE, :PSTDT, :PSTUC, :PENUC, :PSTVT, :PENVT ) OPBAL,
INFOTBLM.DEBIT    ( L5.PKCODE, :PSTDT,:PENDT, :PSTUC, :PENUC, :PSTVT, :PENVT ) AMNTDR,
INFOTBLM.CREDIT ( L5.PKCODE, :PSTDT,:PENDT, :PSTUC, :PENUC, :PSTVT, :PENVT ) AMNTCR

FROM   FSLVL  L1, FSLVL L2,  FSMAST L5

WHERE  L2.FKCODE  =  L1.PKCODE
AND        L5.FKCODE  =  L2.PKCODE

AND        L5.PKCODE Between :PSTCD AND NVL(:PENCD,:PSTCD)

GROUP BY  L1.PKCODE ,  L1.NAME , L1.LVL ,
                 L2.PKCODE , L2.NAME ,  L2.LVL ,
                 L5.PKCODE , L5.NAME 

ORDER BY L1.PKCODE, L2.PKCODE,  L5.PKCODE