Since EXTEND is custom functionality, it seems reasonable that we could have a switch. Given that SQL Server and Postgres support it seems reasonable to support the table functions without the TABLE syntax.
I for one definitely think the TABLE syntax is much more confusing to use, especially in the example that we're looking to support, such as: select * from dfs.`/myfolder/mytable` (type => 'CSV', fieldDelimiter => '|', skipFirstRow => true) This seems much clearer than: select * from TABLE(dfs.`/myfolder/mytable` (type => 'CSV', fieldDelimiter => '|', skipFirstRow => true)) It also looks much more like a hint to the table (which is our goal). -- Jacques Nadeau CTO and Co-Founder, Dremio On Fri, Nov 6, 2015 at 9:15 PM, Julian Hyde <[email protected]> wrote: > Thanks for doing the legwork and finding what the other vendors do. It is > indeed compelling that SQL Server and Postgres go beyond the standard an > make the TABLE keyword optional. > > I tried that syntax in Calcite and discovered that there is a clash with > one of our own (few) extensions. In > https://issues.apache.org/jira/browse/CALCITE-493 we added the EXTENDS > clause. You can write > > SELECT * > FROM Emp EXTEND (favoriteBand VARCHAR(100), golfHandicap INTEGER) > WHERE goldHandicap < 10; > > to tell Calcite that there are two undeclared columns in the Emp table but > you would like to use them in this particular query. We chose to make the > EXTEND keyword optional, so you could instead write > > SELECT * > FROM Emp (favoriteBand VARCHAR(100), golfHandicap INTEGER) > WHERE goldHandicap < 10; > > That is uncomfortably close to > > SELECT * > FROM EmpFunction (favoriteBand, golfHandicap); > > so we would require > > SELECT * > FROM TABLE(EmpFunction (favoriteBand, golfHandicap)); > > if EmpFunction was a table-function. You could combine the two forms like > this: > > SELECT * > FROM TABLE(EmpFunction (favoriteBand, golfHandicap)) EXTEND > (anotherAttribute INTEGER); > > We could revisit whether EXTEND is optional, I suppose. But we should also > ask whether requiring folks to type TABLE is such a hardship. > > Julian > > > > On Nov 6, 2015, at 2:20 PM, Julien Le Dem <[email protected]> wrote: > > > > - Table function syntax: I did a quick search and it seems there's no > > consensus about this. > > It seems that Posgres [1] and SQL Server [2] both allow calling table > > functions without the table(...) wrapper while Oracle [3] and DB2 [4] > > expect it. > > MySQL does not have table functions [5] > > 2 for, 2 against and 1 undecided: that's a draw :) > > Would it be reasonable to allow a switch in the grammar generation to > have > > a posgres compatible syntax? Currently in Drill we use the MySQL like > > syntax (back ticks for identifiers etc) > > > > [1] http://www.postgresql.org/docs/7.3/static/xfunc-tablefunctions.html > > [2] https://technet.microsoft.com/en-us/library/aa214485(v=sql.80).aspx > > [3] https://oracle-base.com/articles/misc/pipelined-table-functions > > [4] http://www.ibm.com/developerworks/ibmi/library/i-power-of-udtf/ > > [5] > > > http://stackoverflow.com/questions/12163666/mysql-function-to-return-a-table > > > > - It seems a simple change in SqlCallBinding fixes the function > > overloading: https://github.com/apache/calcite/pull/166/files > > But that seems too easy to be true. Possibly this method is called more > > than once (before and after the function has been resolved?) > > > > FYI this would happen only when using named parameter. We do want to > > overload in this case, which is why I'm looking into it. > > > > I'll fill a JIRA for my other branch > > > > Julien > > > > On Thu, Nov 5, 2015 at 5:39 PM, Julian Hyde <[email protected]> wrote: > > > >> > >> On Nov 5, 2015, at 5:00 PM, Julien Le Dem <[email protected]> wrote: > >> > >> TL;DR: TableMacro works for me; I need help with a bug in Calcite when > >> there's more than 1 function with the same name. > >> > >> > >> Yes; see below. > >> > >> FYI: I have a prototype of TableMacro working in Drill. For now just > being > >> able to specify the delimiter for csv files. > >> So it seem the answer to my question 1) is that TableMacros are the way > to > >> go. > >> I'm still wondering about *3) is the table(...) wrapping syntax > >> necessary?* > >> > >> > >> Consider: > >> > >> select * from myTable as f(x, y) > >> select * from myTable f(x, y) > >> select * from myFunction(x, y) > >> > >> #1 and #2 mean the same thing; #2 and #3 look awfully similar. Also, if > f > >> is a function with zero arguments, could you invoke it like this?: > >> > >> select * from f > >> > >> I don’t know the actual rationale. But I know that the SQL standards > >> people in their wisdom decided to add a keyword to disambiguate. > >> > >> I had to fix some things in Calcite to enable this: > >> https://github.com/dremio/calcite/pull/1/files > >> Drill uses Frameworks.getPlanner() that does not seem to be used in > >> Calcite for the Maze example. > >> Which is why some hooks were missing. > >> > >> > >> Can you log a jira case to track this bug? > >> > >> > >> I think I found a bug in Calcite but I'd need help to fix it. > >> Here is a test that reproduces the problem: > >> https://github.com/apache/calcite/pull/166 > >> If we return more than 1 TableFunction with the same name, we get a NPE > >> later on. > >> > >> > >> Yes, I knew there was a problem with overloading. Please log a JIRA case > >> on resolution of overloaded functions when invoked with named arguments. > >> (It probably applies to all functions, not just table functions.) The > fix > >> will take a while (if you wait for me to write it). > >> > >> For now please tell your users not to overload. :) > >> > >> > >> Julian > >> > >> > > > > > > -- > > Julien > >
