Hi Dominik, To add to Rui's answer. there are other examples I can think of on how to extend Calcite's DDL syntax is already in Calcite's Server module [1] and one of our open-sourced project [2]. you might want to check them out.
-- Rong [1] https://github.com/apache/calcite/blob/master/server/src/main/codegen/includes/parserImpls.ftl [2] https://github.com/uber/AthenaX/blob/master/athenax-vm-compiler/src/codegen/includes/parserImpls.ftl On Mon, Sep 16, 2019 at 8:28 PM Rui Li <lirui.fu...@gmail.com> wrote: > Hi Dominik, > > I think you can check "parserImpls.ftl" to find out how Flink extends > Calcite's original syntax to support features like CREATE TABLE and DROP > TABLE, and follow those examples to implement your own syntax. It may also > be helpful to check the pom.xml of flink-sql-parser to see how we use > javacc plugin to generate the parser code. > At the moment I don't think there's any tutorials about extending the SQL > parser because it's quite internal to Flink. But perhaps the following > answer provides some insights about how to extend Calcite parser in > general: > https://stackoverflow.com/questions/44382826/how-to-change-calcites-default-sql-grammar > > On Tue, Sep 17, 2019 at 12:16 AM > dominik.werner.groenin...@student.uni-augsburg.de < > dominik.werner.groenin...@student.uni-augsburg.de> wrote: > >> Hey there, >> >> >> >> I have to extend Flink's SQL-parser such that it accepts and evaluates >> select-queries with different syntax. >> >> Furthermore I use Eclipse Oxygen with Maven plugin and Flink Release 1.8. >> 0. >> >> >> >> What I believe to know: >> >> For parsing SQL-queries Flink-Table uses Apache Calcite's SQL-parser. >> Flink-Table-Planner is the only module that references the Calcite-Core >> which contains the parser ("Parser.jj" ?). >> >> Therefore I want to import Flink-Table-Planner and Calcite-Core as local >> projects in Eclipse and edit the files "config.fmpp" and "parserImpls.ftl". >> After that I want to create a new "Parser.jj" file with Apache Freemaker (I >> assume there are some tutorials?). >> >> >> >> What I don't know: >> >> Is it a promising plan or are there better strategies to extend the >> parser? >> >> I already tried to import Flink-Table-Planner but I got many errors which >> might refer to a Scala-problem with Eclipse. Do I have to switch to say >> IntelliJ? Furthermore I'm not yet clear about how exactly I can extend the >> parser. Are there any manuals/tutorials to teach me adding a new >> SELECT-syntax? I already came across the parser extension test but it >> didn't give me the answers I was looking for. >> >> >> >> Thanks for your help! >> >> >> >> Regards, >> >> Dominik Gröninger >> >> >> >> > > > -- > Best regards! > Rui Li >
