在Oracle中计算单列

Question

我有如下表：

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

我想更新列pijut从结果jancuk列。 在oracle中使用查询是否可能？
因此，如果表已更新，则该表应如下所示：

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

请帮帮我。 谢谢。

Answer 1

您可以将函数与动态SQL结合使用-

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;
/

结果选择将是-

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

Answer 2

尝试：

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

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