[Firebird-devel] Subselect as PSQL expressions (was: Small regression in HEAD's PSQL)

[Adriano d. S. F. <adr...@gm...>]

Leyne, Sean wrote:
> Adriano,
>
>   
>> Instead of try some other way to fix this problem and CORE-2538 at the
>> same time, I'd like to propose a new thing.
>>
>> Currently, we explicitly make it impossible to do things as:
>>     var = (select ... from ...);
>>     if ((select ... from ...) = 1) then
>>
>> Apparently, that works ok. Won't it be much better to revert CORE-2538
>> and eliminate this prohibition?
>>     
>
> I'm not sure if I understand what exactly you are proposing, I find your post a little confusing.
>
> Please elaborate.
Now:

SQL> execute block
CON> as
CON>   declare n integer;
CON> begin
CON>   if ((select 1 from rdb$database) = 0) then
CON>      n = 1;
CON> end!
Statement failed, SQLSTATE = 42000
Dynamic SQL Error
-SQL error code = -206
-Subselect illegal in this context

I propose this code should compile and work. Why not?

At the same time, the regression is fixed without rollback CORE-2538 fix
or found another "clever" solution.


Adriano