Builder Pattern

Based on the provided code snippet, the appropriate design pattern for implementation is the Builder pattern. This pattern allows us to separate the construction of a complex object from its representation. In this case, we can use the Builder pattern to construct the Sales Modified query in a step-by-step manner, making it more readable and maintainable.

Here's a basic code snippet that adheres to the principles of the Builder pattern:

class SalesModifiedBuilder:
    def __init__(self):
        self.sales_query = None
    
    def generate_query(self):
        self.sales_query = (
            SUMMARIZE(
                FILTER(
                    ADDCOLUMNS(
                        ALL(Sales),
                        "Total Sales", [Qty] * [Price],
                        "Discount Sales", [Qty] * [Price] * (1 - [Discount])
                    ),
                    [Total Sales] <> [Discount Sales]
                ),
                [Product],
                "Total Regular Sales", SUM([Total Sales]),
                "Total Discounted Sales", SUM([Discount Sales]),
                "Discount Savings", SUM([Total Sales]) - SUM([Discount Sales])
            )
        )

    def get_query(self):
        return self.sales_query

You can then use the builder to generate the Sales Modified query like this:

builder = SalesModifiedBuilder()
builder.generate_query()
sales_modified_query = builder.get_query()

By using the Builder pattern, we can easily modify the construction process of the Sales Modified query and provide a clear interface for constructing complex queries. This approach also enhances code reusability and allows for more flexible query construction in the future if needed.