On reflection, I still think that DEFAULT should be a reserved keyword. But I don’t think that wouldn’t prevent us from supporting it as a prefix to a table name in the core parser.
Are the deliberations of Hive or Trino (Presto/PrestoDB) public? I’d like to know their rationale. Julian > On Apr 12, 2022, at 11:40 AM, Julian Hyde <jhyde.apa...@gmail.com> wrote: > > DEFAULT is from the SQL standard. You can use it when invoking UDFs with > named parameters, e.g. > > SELECT myFun(p1 => 1, p2 => DEFAULT, p3 => 3) > FROM t > > and in an INSERT statement: > > INSERT INTO t (x, y, z) VALUES (1, DEFAULT, 2) > > as long as parameter p2 and column y have default values. > > So yes, DEFAULT should be a reserved keyword. And Hive screwed up by not > reading the standard. > > If there is a database or schema called DEFAULT then you can quote it, e.g. > > SELECT * > FROM “DEFAULT”.t > > We could consider making DEFAULT non-reserved in the Babel parser. > > Julian > > > > >> On Apr 12, 2022, at 9:06 AM, Gavin Ray <ray.gavi...@gmail.com> wrote: >> >> The hacky way would be to add a grammar clause like this I think: >> >> | "DEFAULT" >> >> To the "TableRef2" node in the parser grammar: >> https://github.com/apache/calcite/blob/82dd78a14f6aef2eeec2f9c94978d04b4acc5359/core/src/main/codegen/templates/Parser.jj#L2087-L2276 >> >> Not sure all the implications this would have elsewhere though. >> >> Also for personal opinion -- the notion of a "DEFAULT" database I'm not >> sure is a universal thing. >> I've never worked with analytical DB's, only Postgres/MySQL -- and in these >> DB's the default database is implicit in your queries. >> >> IE if I connect to a database called "mydb", all queries are automatically >> prefixed implicitly with "mydb." >> >> MySQL I don't think has a default database. A brand-new MySQL DB has 0 >> databases. >> There is one called "mysql" but that's a system DB, like "pg_catalog" or >> "information_schema". >> >> Confusingly this is different in Postgres, where the "postgres" DB is one >> that exists by default >> and IS intended to be a user-facing DB. >> >> >> On Mon, Apr 11, 2022 at 11:36 PM Yanjing Wang <zhuangzixiao...@gmail.com> >> wrote: >> >>> Hi community, >>> >>> In hive, DEFAULT is a default database, so one can write sql >>> SELECT * FROM DEFAULT.t >>> >>> In trino, one can write >>> SELECT * FROM HIVE.DEFAULT.t >>> >>> But now Calcite treat DEFAULT as a keyword which will be resolved to >>> DEFAULT() function. >>> >>> What should I do to make the parser to support the DEFAULT in the table >>> identifier? >>> >>> I tried to add the DEFAULT to non-keywords but it would cause DEFAULT() >>> function fails. >>> >>> Now I must tell the user wrap the DEFAULT using quotes like this >>> SELECT * FROM HIVE."DEFAULT".t >>> >>> Thanks in advance. >>> >
