[jira] [Commented] (CALCITE-2280) Liberal "babel" parser that accepts all SQL dialects

["Xuefu Zhang (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CALCITE-2280?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16650899#comment-16650899 ] 

Xuefu Zhang commented on CALCITE-2280:
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Hi [~julianhyde] With my limited understanding of this change, I assume we have put a boiler place for extending Calcite grammar to accommodate any specialties in any SQL dialects. This is great!

On the other hand, I'm curious about whether we can provide, or have a plan to do so, a conformance level for Hive QL as a whole, similar to MySQL, given the popularity of Hive QL in the big data world. 

Could you shed some light on this? Thanks.

> Liberal "babel" parser that accepts all SQL dialects
> ----------------------------------------------------
>
>                 Key: CALCITE-2280
>                 URL: https://issues.apache.org/jira/browse/CALCITE-2280
>             Project: Calcite
>          Issue Type: Bug
>          Components: babel
>            Reporter: Julian Hyde
>            Assignee: Julian Hyde
>            Priority: Major
>             Fix For: 1.17.0
>
>
> Create a parser that accepts all SQL dialects.
> It would accept common dialects such as Oracle, MySQL, PostgreSQL, BigQuery. If you have preferred dialects, please let us know in the comments section. (If you're willing to work on a particular dialect, even better!)
> We would do this in a new module, inheriting and extending the parser in the same way that the DDL parser in the "server" module does.
> This would be a messy and difficult project, because we would have to comply with the rules of each parser (and its set of built-in functions) rather than writing the rules as we would like them to be. That's why I would keep it out of the core parser. But it would also have large benefits.
> This would be new territory Calcite: as a tool for manipulating/understanding SQL, not (necessarily) for relational algebra or execution.
> Some possible uses:
> * analyze query lineage (what tables and columns are used in a query);
> * translate from one SQL dialect to another (using the JDBC adapter to generate SQL in the target dialect);
> * a "deep" compatibility mode (much more comprehensive than the current compatibility mode) where Calcite could pretend to be, say, Oracle;
> * SQL parser as a service: a REST call gives a SQL query, and returns a JSON or XML document with the parse tree.
> If you can think of interesting uses, please discuss in the comments.
> There are similarities with Uber's [QueryParser|https://eng.uber.com/queryparser/] tool. Maybe we can collaborate, or make use of their test cases.
> We will need a lot of sample queries. If you are able to contribute sample queries for particular dialects, please discuss in the comments section. It would be good if the sample queries are based on a familiar schema (e.g. scott or foodmart) but we can be flexible about this.



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