pql

Module to interact with PQL queries.

This module contains class to interact with PQL queries including columns and filters.

Typical usage example:

```python
query = PQL(distinct=True)
query += PQLColumn(name="column", query='"TABLE"."COLUMN"')
query += PQLFilter(query='FILTER "TABLE"."COLUMN" = 1;')
query += OrderByColumn(query='"TABLE"."COLUMN"', ascending=False)
```