maria-developers team mailing list archive

[Oleksandr Byelkin <sanja@xxxxxxxxxxxxxxxx>]

Am 26.02.20 um 22:15 schrieb Sergei Golubchik:
> Hi, Oleksandr!
>
> On Feb 26, Oleksandr Byelkin wrote:
> > On Wed, Feb 26, 2020 at 1:44 PM Sergei Golubchik <serg@xxxxxxxxxxx> wrote:
> >
> > > Hi, Sanja!
> > >
> > > _some_ comments are below.
> > >
> > > The main thing, I still don't understand your changes in sql_select.cc.
> > >
> > > Why did you create separate counters and code paths with if() for CYCLE?
> > > I'd think it could be just a generalization of DISTINCT
> > DISTINCT makes all fields distinct, except hidden, I need also except come
> > other (or better say by list of not hidden)
> Exactly. I thought DISTINCT will be just CYCLE with an empty list of
> non-distinct columns. Or something like that. Not like
>
>    if (cycle) {
>      cycle code
>    } else {
>      distinct code
>    }

and how it will help if include/exclude decided on level of each field 
(when distinct is a global for whole )?

I can of course write separate function or branch for cycle, but it will 
heavy duplicate code of distinct.

> > > > --- a/sql/sql_cte.cc
> > > > +++ b/sql/sql_cte.cc
> > > > @@ -982,6 +982,38 @@ With_element::rename_columns_of_derived_unit(THD *thd,
> > > are you sure what you're doing below can still be called
> > > "rename_columns_of_derived_unit" ?
> > I can rename it to prepare_olumns_of_derived_unit, is it OK?
> anything you like :)
OK
> > > > +opt_cycle:
> > > > +         /* empty */
> > > > +         { $$= NULL; }
> > > > +         |
> > > > +         CYCLE_SYM
> > > > +         {
> > > > +           if (!Lex->curr_with_clause->with_recursive)
> > > > +           {
> > > > +             thd->parse_error(ER_SYNTAX_ERROR, $1.pos());
> > > > +           }
> > > > +         }
> > > > +         '(' with_column_list ')'
> > > Where did you see that the standard requires parentheses here?
> > Maybe in ORACLE docs... but without it it creates a lot of conflicts.
> The standard says no parentheses. What kind of conflicts do you get?
shift-reduce conflicts
> Regards,
> Sergei
> VP of MariaDB Server Engineering
> and security@xxxxxxxxxxx
>
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