feat: Firebolt dialect

[betodealmeida]

We found a problem when using sqlglot in Apache Superset to process (parse, modify the AST, and re-render) Firebolt queries. The problem happens when we run a query with a predicate of col NOT IN and it gets translated to NOT col IN by the generic parser:

>>> sqlglot.parse_one("SELECT * FROM tbl WHERE i NOT IN (1, 2)").sql()
'SELECT * FROM tbl WHERE NOT i IN (1, 2)'

While both queries are semantically equivalent, the first one is valid in Firebolt, while the second is not. This happens because NOT has higher precedence than IN:

CREATE TABLE tbl (i INT, b BOOLEAN, t TEXT);
INSERT INTO tbl VALUES (0, FALSE, 'false'), (1, TRUE, 'true');
SELECT * FROM tbl WHERE NOT i IN (1, 2);

firebolt error: - Line 4, Column 25: operator 'not' for input types (integer) not found, try adding explicit casts

This only happens when checking for a range; equality (and other comparisons) works as expected:

SELECT * FROM tbl WHERE NOT i = 1;   -- this works

This PR introduces a custom Firebolt dialect that fixes the problem:

>>> sqlglot.parse_one("SELECT * FROM tbl WHERE i NOT IN (1, 2)").sql("firebolt")
'SELECT * FROM tbl WHERE NOT (i IN (1, 2))'