計算單列甲骨文

Question

我有表如下：

id  jancuk  pijut 
------------------------------- 
1  20 * 4   
2   2 + 4   
3  3 - 1 + 2   
4  20/5 

我想從jancuk列更新結果列pijut。這在使用查詢的oracle中可能嗎？
所以，如果表已經更新，那麼這個表應該是這個樣子的：

id  jancuk  pijut 
------------------------------- 
1  20 * 4   80 
2   2 + 4   6 
3  3 - 1 + 2   4 
4  20/5   4 

請幫助我。謝謝。

Answer 1

：

update tbl 
set "pijut" = xmlquery(replace("jancuk", '/', ' div ') returning content).getNumberVal(); 

欲瞭解更多信息link

Answer 2

您可以使用功能與動態SQL來做到這一點 -

create or replace function calc_value(str in varchar2) return number is 
val_ number; 
begin 
    if str is null then 
     return null; 
    end if; 
    execute immediate 'begin :val_ := '||str||'; end;' using out val_; 
    return val_; 
end; 
/

和結果選擇將是 -

嘗試

with t as 
(
select 1 as id, '  20 * 4 ' as jancuk from dual union all 
select 2 as id, '   2 + 4 ' as jancuk from dual union all  
select 3 as id, '  3 - 1 + 2 ' as jancuk from dual union all  
select 4 as id, '  20/5 ' as jancuk from dual 
) 
select id, jancuk, calc_value(jancuk) as pijut 
from t