Design SQL-Like Python Class | Dataford Interview Questions

Design a SQL-like class in Python that can perform methods on a dictionary that mimic SQL operations.

Implement a reusable query engine over one column-oriented dictionary, supporting filtering, column selection, ordering, distinct results, limits, grouping, and basic aggregations. The input table maps column names to equally sized lists, and operations are provided as a dictionary. Return an ordered list of row dictionaries with deterministic column ordering.

Constraints

The table contains zero or more columns, and all columns have equal length.
Column names are strings and values are comparable when used with ordering or predicates.
Supported operators are =, !=, <, <=, >, >=, and in.
Supported aggregates are count, sum, min, max, and avg.
Operations are applied in the order: where, grouping and projection, distinct, order_by, limit.
The input contains at most 10^4 rows and 100 columns.

Function Signature

def execute_query(table, operations):

Your question is Design SQL-Like Python Class. Start with the requirements in the Question tab.

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Problem

Design a SQL-like class in Python that can perform methods on a dictionary that mimic SQL operations.

Constraints

The table contains zero or more columns, and all columns have equal length.
Column names are strings and values are comparable when used with ordering or predicates.
Supported operators are =, !=, <, <=, >, >=, and in.
Supported aggregates are count, sum, min, max, and avg.
Operations are applied in the order: where, grouping and projection, distinct, order_by, limit.
The input contains at most 10^4 rows and 100 columns.

Function Signature

def execute_query(table, operations):

Your question is Design SQL-Like Python Class. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.