Can (should) things inside back ticks be callable? I guess this makes a very difficult situation from a usability standpoint because user is a not uncommon column name (think security logs, web logs, etc) yet in the current setup there is lots of possibility for assumptions on calling back tick user back tick and without an error users may have wrong, but "error" free results. On May 23, 2016 4:54 PM, "Jinfeng Ni" <jinfengn...@gmail.com> wrote:
> The problem here is that identifier 'user' is not only a reserved > word, but also represents a special function == current_user() call. > The identifier 'user', whether it's quoted or not, could mean either > column name or the function call. Without the table alias, it could > be ambiguous to sql parser. The table alias informs the parser that > this identifier is not a function call, but a regular identifier, thus > removes the ambiguity. > > This is different from other cases you use quoted reserved word to > represent a column name, since those reserved words do not represent a > special function, thus no ambiguity. > > select `update`, `insert` from dfs.tmp.`1.json`; > +---------+---------+ > | update | insert | > +---------+---------+ > | abc | 100 | > +---------+---------+ > > > > On Mon, May 23, 2016 at 10:44 AM, John Omernik <j...@omernik.com> wrote: > > Ya, as I am testing, this works, however, the users of the system expect > to > > be able to use `user` and while I can provide them instructions to use a > > table alias, I am very worried that they will forget and since it doesn't > > error, but instead puts in a different string, this could lead to bad > > downstream results... > > > > > > > > > > On Mon, May 23, 2016 at 12:41 PM, John Omernik <j...@omernik.com> wrote: > > > >> I filed https://issues.apache.org/jira/browse/DRILL-4692 > >> > >> I see an alias would work as a tmp fix, but this should be address (I > >> wonder if other words may have a problem too?) > >> > >> > >> > >> On Mon, May 23, 2016 at 12:38 PM, Andries Engelbrecht < > >> aengelbre...@maprtech.com> wrote: > >> > >>> Hmm interesting. > >>> > >>> As a workaround just use a table alias when referencing the column. > >>> > >>> > >>> Might be good to se if there is a JIRA for this, or file one if not. > >>> > >>> --Andries > >>> > >>> > On May 23, 2016, at 10:28 AM, John Omernik <j...@omernik.com> wrote: > >>> > > >>> > I have data with a field name user. > >>> > > >>> > When I select, with backticks, it doesn't show the field, but > instead my > >>> > current logged in user... > >>> > > >>> > > >>> > select CONVERT_FROM(`user`, 'UTF8') as `user` from table limit 10; > >>> > > >>> > > >>> > Shouldn't the backticks allow me to reference the field properly? > >>> > > >>> > John > >>> > >>> > >> >
