This repo is a work in progress, looking to explore how some tools fit together, and do some hello-world-y stuff w/ Antlr4.
pip install -r requirements.txtwget https://raw.githubusercontent.com/antlr/grammars-v4/master/sql/snowflake/SnowflakeLexer.g4
wget https://raw.githubusercontent.com/antlr/grammars-v4/master/sql/snowflake/SnowflakeParser.g4Use antlr4 from the antlr4-tools pip pacakge to compile the grammars to python code:
antlr4 -Dlanguage=Python3 SnowflakeLexer.g4
antlr4 -Dlanguage=Python3 SnowflakeParser.g4Next, we can parse the small example query, shown below from query_small.sql:
SELECT COUNT(*) as weekly_active_users
FROM users
WHERE DATEDIFF('day', last_active, CURRENT_TIMESTAMP) < 7cat query_small.sql | python print_query_tree.pyThis will print the parsed tree for the query
(query_statement
(select_statement
(select_clause SELECT
(select_list_no_top
(select_list
(select_list_elem
(expression_elem
(expr
(function_call
(aggregate_function
(id_
(builtin_function COUNT))
( * ))))
(as_alias AS
(alias
(id_ weekly_active_users))))))))
(select_optional_clauses
(from_clause FROM
(table_sources
(table_source
(table_source_item_joined
(object_ref
(object_name
(id_ active_users)))))))
(where_clause WHERE
(search_condition
(predicate
(expr
(ternary_builtin_function DATEDIFF)
(
(expr
(primitive_expression
(literal 'day'))),
(expr
(primitive_expression
(id_ last_active))),
(expr
(primitive_expression
(id_
(builtin_function CURRENT_TIMESTAMP)))) ))
(comparison_operator <)
(expr
(primitive_expression
(literal 7)))))))))
Try it yourself with the larger, more complex query.
cat query_big.sql | python print_query_tree.py- Antlr4 Website - @
- Python 3 Examples from Antlr4 Book - @jszheng
- Antlr4-Python - @AlanHohn
- Snowflake Grammar for Antlr4
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