README.md

Bigquery SQL Parser

Simple and out of the box Bigquery SQL Parser for python. Convert your SQL into python object which you can modify programatically.

Installation

pip3 install bigquery-sql-parser

Usage

Since the SQL will be converted to Python object, hence the variable name will be very important to understand.
Please see how we use the variable and terms below.

Query

Below is what we call syntax of query, and Query is the object python name.

# path/query.sql
SELECT
    id,
    name AS customer_name,
FROM
    customer_table AS customer

Column

id, customer_name is columns and we have a Column python object for it.

id is the Column.value as long as the Column.name, but name is Column.value and customer_name is the Column.name

Got the different of value and name of Column object? I hope so.

Python sample:

from bigquery_sql_parser.query import Query

query = Query(your_query_here)
columns = query.columns
for column in query.columns
	print(column.value, column.name)

#> id, id
#> name, customer_name

Table

You can just get the table name by calling Query Object Query.full_table_ids

from bigquery_sql_parser.query import Query

query = Query(your_query_here)
print(query.full_table_ids)

CTE

Well, if you use CTE like this

WITH
cte1 AS (
	xxxx
),
cte2 AS (
	xxxx
)
SELECT *
FROM cte2,cte1

It can't using Query object directly, you need to use Script instead

from bigquery_sql_parser.script import Script
from bigquery_sql_parser.query import Query

script = Script.from_file('query_path.sql')
cte_list = script.ctes
for cte in cte_list:
	print(cte.name)
	print(cte.text)

	query = Query(cte.text)
	query... # any query variable can call here

Blocks

Since BigQuery support scripting, sometime you might want to scan query that has a lot of blocks and use Semicolon as separator.

CREATE FUNCTION x AS (());
DELETE TABLE x;
INSERT INTO x;
WITH cte1 AS (
	SELECT * FROM table
)
SELECT
    a AS b,
    c AS d
FROM table_1

It can't using Query object directly, you need to use Script instead

from bigquery_sql_parser.script import Script
from bigquery_sql_parser.query import Query

script = Script.from_file('query_path.sql')
blocks = script.blocks
for block in blocks:
	if block.is_cte_statement and block.is_select_statement:
		print(cte.name)
		print(cte.text)
		cte_query = Query(cte.text)
		cte_query...

	final_query = Query(block.final_cte_query)
	final_query...

And keep counting for others to supported...

• Where/Filter statement Object
• Column Functions, Complex Column Composition
• DML Object
• Adding context from BigQuery actual table like its partition, clusters, description, etcs
• Write back from python Object to actual query

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Please make sure to update tests as appropriate.

License

MIT