Simple use of the builder pattern to create a SQL query generator

query_builder.py

class QueryBuilder:
     def __init__(self):
          self.select_value = ''
          self.from_table_name = ''
          self.where_value = ''
          self.groupby_value = ''

     def select(self, select_arg):
          self.select_value = select_arg
          return self

     def from_table(self, from_arg):
          self.from_table_name = from_arg
          return self
          
     def where(self, where_arg):
          self.where_value = where_arg
          return self
          
     def groupby(self, groupby_args):
          self.groupby_value = groupby_args
          return self
          
     def build(self):
          if self.where_value:
               where_clause = f'WHERE {self.where_value}'
          if self.groupby_value:
               groupby_clause = f'GROUP BY {self.groupby_value}'

          return f"""
               SELECT {self.select_value}
               FROM {self.from_table_name}
               {where_clause}
               {groupby_clause}
          """

# Simple builder pattern example for building queries
query = QueryBuilder()
query.select('Customer, Region, SUM(SaleValue)') \
     .from_table('Sales') \
     
     # Optional - add where and groupby clauses. 
     # Object construction can easily be either simple or complex
query.where('DATEDIFF(day, TimeStamp, CURRENT_TIMESTAMP) < 180') \
     .groupby('Customer, Region')

# Builder pattern collects the optional arguments and builds the actual SQL text
query_text = query.build()

"""
query_text value:
SELECT Customer, Region, SUM(SaleValue)
FROM Sales
WHERE DATEDIFF(day, TimeStamp, CURRENT_TIMESTAMP) < 180
GROUP BY Customer, Region
"""