oracle 如何转换select中函数返回的布尔值
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How to convert boolean value which returned by function in select
提问by Horman Lewis
I had a next query, which doesn't work:
我有一个下一个查询，它不起作用：
SELECT case BasePak.SomeFunction(333,4,5555) when true then 1 else 0 end
from dual
BasePak.SomeFunction(333,4,5555) returns boolean value. How to convert result(true, false) to number or string?
BasePak.SomeFunction(333,4,5555) 返回布尔值。如何将结果（真，假）转换为数字或字符串？
I tried cast function but not successful.
我尝试了强制转换功能但没有成功。
Is there any way to convert boolean to int or string?
有没有办法将 boolean 转换为 int 或 string？
回答by Michal
SQL does not have boolean datatype, but PL/SQL does. In PL/SQL you have more options. You can:
SQL 没有布尔数据类型，但 PL/SQL 有。在 PL/SQL 中，您有更多选择。你可以：
- write functions so they don't return boolean, but the type you need.
- if you can't edit the functions, you can write a wrapper function, that does the conversion
or you can directly use code like this:
string_var := CASE WHEN boolean_var THEN 'True' WHEN NOT boolean_var -- or ELSE, depending on what you want THEN 'False' END;
- 编写函数，使它们不返回布尔值，而是返回您需要的类型。
- 如果你不能编辑这些函数，你可以写一个包装函数来进行转换
或者你可以直接使用这样的代码：
string_var := CASE WHEN boolean_var THEN 'True' WHEN NOT boolean_var -- or ELSE, depending on what you want THEN 'False' END;
In your case, I would either change the original function or write a wrapper function and use it directly from SQL code.
在您的情况下，我要么更改原始函数，要么编写一个包装函数并直接从 SQL 代码中使用它。
回答by DLR
As far as i know SQL doesn't contain a Boolean datatype. A Bit is generally used to represent true (1) or false (0). Are you sure your function is not returning a NULL value as this needs to be handled differently
据我所知，SQL 不包含布尔数据类型。A Bit 通常用于表示真 (1) 或假 (0)。您确定您的函数没有返回 NULL 值，因为这需要以不同的方式处理
Try this instead:
试试这个：
SELECT case when BasePak.SomeFunction(333,4,5555) = 1 then 'true' else 'False' end
from dual
