PySquel

POC for linting SQL statements in Python.

Relying on sqlfluff.

The name is inspired by Czech word paskvil which means messed up.

Concept

Using str subclass called sql to mark all SQL statements for linting. It causes avoidance of parsing the SQL statements from all strings.

from pysquel import sql

my_sql = sql("SELECT * FROM table")

# `sql` is a just subclass of the str
>>> type(my_sql)
<class 'str'>

>>> sql("SELECT * FROM {table}").format(table="super_table")
'SELECT * FROM super_table'

It could be better in the future:

• tagstr

  sql"SELECT FROM table"
  
  sql_f"SELECT FROM {table}"
  

• dedent

  sql_d"""
    SELECT 
    FROM table
  """
  
  sql_df"""
    SELECT 
    FROM {table}
  """
  

Usage

# tests/test_lint.py

from pysquel import sql

bad_sql = sql(
    """
  SELECT * 
FROM 
          table
""")

Run pysquel . to lint all sql statements in the current directory:

tests/test_lint.py :
--------------------------------------------------------------------------------
  SELECT * 
FROM 
          table

--------------------------------------------------------------------------------
{'line_no': 1, 'line_pos': 1, 'code': 'LT01', 'description': "Expected only single space before 'SELECT' keyword. Found '  '.", 'name': 'layout.spacing'}
{'line_no': 1, 'line_pos': 1, 'code': 'LT02', 'description': 'First line should not be indented.', 'name': 'layout.indent'}
{'line_no': 1, 'line_pos': 1, 'code': 'LT13', 'description': 'Files must not begin with newlines or whitespace.', 'name': 'layout.start_of_file'}
{'line_no': 1, 'line_pos': 3, 'code': 'AM04', 'description': 'Query produces an unknown number of result columns.', 'name': 'ambiguous.column_count'}
{'line_no': 1, 'line_pos': 11, 'code': 'LT01', 'description': 'Unnecessary trailing whitespace.', 'name': 'layout.spacing'}
{'line_no': 2, 'line_pos': 5, 'code': 'LT01', 'description': 'Unnecessary trailing whitespace.', 'name': 'layout.spacing'}
{'line_no': 3, 'line_pos': 1, 'code': 'LT02', 'description': 'Expected indent of 4 spaces.', 'name': 'layout.indent'}
================================================================================

TODO

• config
• exclude rules
• exclude dirs
• noqa
• sqlfluff config (dialect, templating, ...)
• custom token instead of sql?
• lint missing sql prefix for potential SQL statements