BigQuery INFORMATION_SCHEMA views not parsed properly?

BigQuery has INFORMATION_SCHEMA views that don’t seem to parse properly using sqlglot?

For example: sqlglot.parse_one("SELECT * FROM project.dataset.INFORMATION_SCHEMA.TABLES", read="bigquery") gives:

(SELECT expressions:
  (STAR ), from:
  (FROM expressions:
    (TABLE this:
      (IDENTIFIER this: TABLES, quoted: False), db:
      (IDENTIFIER this: INFORMATION_SCHEMA, quoted: False), catalog:
      (IDENTIFIER this: dataset, quoted: False))))

which leaves out the project part completely. Not quite sure what the correct behavior would be though!

[barakalon]

I don’t think it makes sense for a column to have a db. Columns select from the tables available in the current scope. They aren’t references to the column itself.

But I think the matter at hand is Table expressions, not Column expressions.

Tables allow for catalog, db, and table. Seems like Bigquery allows for further namespacing, which I don’t think is standard. So we want to gracefully handle this case by nesting the table in an arbitrary number of Dot expressions.

[GeorgeSittas]

Regarding columns, is the following syntax tree what we’re after?

>>> sqlglot.parse_one("SELECT INFORMATION_SCHEMA.TABLES.TABLE_NAME")
(SELECT expressions:
  (DOT this:
    (COLUMN this:
      (IDENTIFIER this: TABLES, quoted: False), table:
      (IDENTIFIER this: INFORMATION_SCHEMA, quoted: False)), expression:
    (IDENTIFIER this: TABLE_NAME, quoted: False)), from:
  (FROM expressions:
    (TABLE this:
      (IDENTIFIER this: TABLES, quoted: False), db:
      (IDENTIFIER this: INFORMATION_SCHEMA, quoted: False))))

The alternative form I had in mind given the context is:

>>> sqlglot.parse_one("SELECT INFORMATION_SCHEMA.TABLES.TABLE_NAME")
(SELECT expressions:
  (COLUMN this:
    (IDENTIFIER this: TABLE_NAME, quoted: False), table:
    (IDENTIFIER this: TABLES, quoted: False), db:
    (IDENTIFIER this: INFORMATION_SCHEMA, quoted: False)), from:
  (FROM expressions:
    (TABLE this:
      (IDENTIFIER this: TABLES, quoted: False), db:
      (IDENTIFIER this: INFORMATION_SCHEMA, quoted: False))))