Phoenix already supports columns at read-time using the syntax without the EXTENDS keyword as Julian indicated: SELECT * FROM Emp (favoriteBand VARCHAR(100), golfHandicap INTEGER) WHERE goldHandicap < 10;
Changing this by requiring the EXTENDS keyword would create a backward compatibility problem. I think it'd be good if both of these extensions worked in Drill & Phoenix given our Drillix initiative. On Sat, Nov 7, 2015 at 3:34 PM, Jacques Nadeau <[email protected]> wrote: > My proposal was an a or b using the freemarker template in the grammar, > not something later. > > Actually, put another way: we may want to consider stating that we only > incorporate SQL standards in our primary grammar. Any extensions should be > optional grammar. We could simply have grammar plugins in Calcite (the same > way we plug in external things in Drill). > > Trying to get every project to agree on extensions seems like it may be > hard. > > > > -- > Jacques Nadeau > CTO and Co-Founder, Dremio > > On Sat, Nov 7, 2015 at 2:45 PM, Julian Hyde <[email protected]> wrote: > >> I can see why Jacques wants this syntax. >> >> However a “switch" in a grammar is a bad idea. Grammars need to be >> predictable. Any variation should happen at validation time, or later. >> >> Also, we shouldn’t add configuration parameters as a way of avoiding a >> tough design discussion. >> >> EXTENDS and eliding TABLE are both extensions to standard SQL, and they >> are both applicable to Drill and Phoenix. I think Drill and Phoenix (by >> which I mean Jacques and James, I guess) need to agree what the SQL syntax >> should be. >> >> Julian >> >> >> > On Nov 7, 2015, at 10:40 AM, Jim Scott <[email protected]> wrote: >> > >> > Looking at those two examples I agree with Jacques. The first appears >> more >> > like a hint from the syntactic sugar point of view. >> > >> > >> > On Fri, Nov 6, 2015 at 11:53 PM, Jacques Nadeau <[email protected]> >> wrote: >> > >> >> 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 >> >>> >> >>> >> >> >> > >> > >> > >> > -- >> > *Jim Scott* >> > Director, Enterprise Strategy & Architecture >> > +1 (347) 746-9281 >> > @kingmesal <https://twitter.com/kingmesal> >> > >> > <http://www.mapr.com/> >> > [image: MapR Technologies] <http://www.mapr.com> >> > >> > Now Available - Free Hadoop On-Demand Training >> > < >> http://www.mapr.com/training?utm_source=Email&utm_medium=Signature&utm_campaign=Free%20available >> > >> >> >
