mydb=# select "user" from t1; user ------ ABC I should take back what I said. With quoted identifier, Postgres behaved different from Drill. Both of the interpretations seem to be reasonable, since the identifier could represent two different things.
On Mon, May 23, 2016 at 7:41 PM, Zelaine Fong <[email protected]> wrote: > Jinfeng, > > What does postgres return for the following query in your example? > > select "user" from t1; > > -- Zelaine > > On Mon, May 23, 2016 at 7:39 PM, John Omernik <[email protected]> wrote: > >> Hmm, you are correct, I don't have to like it :) but there is both logic >> and precedence here. Thanks for following up >> >> John >> >> On Monday, May 23, 2016, Jinfeng Ni <[email protected]> wrote: >> >> > An quoted identifier is still an identifier (Drill uses back tick as >> > quote). Per SQL standard, identifier CURRENT_USER / USER/ >> > CURRENT_SESSION/etc are implicit function calls; no () is required. >> > >> > I checked Postgre, and seems it has the same behavior. >> > >> > mydb=# create table t1 (id int, "user" varchar(10)); >> > >> > mydb=# insert into t1 values(100, 'ABC'); >> > INSERT 0 1 >> > >> > mydb=# select * from t1; >> > id | user >> > -----+------ >> > 100 | ABC >> > (1 row) >> > >> > mydb=# select user from t1; >> > current_user >> > -------------- >> > postgres >> > (1 row) >> > >> > mydb=# select t1.user from t1; >> > user >> > ------ >> > ABC >> > (1 row) >> > >> > >> > >> > On Mon, May 23, 2016 at 5:12 PM, John Omernik <[email protected] >> > <javascript:;>> wrote: >> > > 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" <[email protected] >> > <javascript:;>> 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 <[email protected] >> > <javascript:;>> 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 <[email protected] >> > <javascript:;>> 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 < >> > >> >> [email protected] <javascript:;>> 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 <[email protected] >> > <javascript:;>> 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 >> > >> >>> >> > >> >>> >> > >> >> >> > >> >> > >> >> >> -- >> Sent from my iThing >>
