select tel into v_tel from user where ID=‘25’ ;

执行这句就出错，因为user 里面没有ID=25的数据，我想应该是取出空值啊，怎么就抱错啊？

Error 100:ORA-01403: 未找到数据

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select tel into v_tel from user where ID=‘25’

exception

when no_data_found then

v_tel := '-1 ';

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oracle 就是这样

用异常处理吧

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加上异常处理机制NO_DATA_FOUND

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我一般情况下这样写：

select count(0) into v_temp from user where id = '25 '

if v_temp <> 0 then

select tel into v_tel from user where ID=‘25’;

end if;

当然，你也可以使用上面说的捕捉异常

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begin

select tel into v_tel from user where ID=‘25’;

exception

when no_data_found then

v_tel := '-1 ';

end ;