In-Memory SQL Database Task | Dataford Interview Questions

Implement an in-memory SQL database: insert rows into a table, e.g. db.insert("employees", Map.of("id", "1", ...)), where the input columns can be incomplete; then support querying with a WHERE clause such as WHERE name='John' AND id > 5 (AND only, operators =, >, <). Asked in the technical phone screen stage. Multi-part practical coding problem; interviewer gives method calls and expected output rather than a full problem statement.

Output

Return one row per employee matching both conditions.
Include id, name, email, and department.
Sort by id ascending, preserving NULL values for omitted columns.

Schema

employees

Column	Type	Description
idPK	INT	Unique employee identifier
name	VARCHAR(100)	Employee name, which may be omitted
email	VARCHAR(255)	Employee email address
department	VARCHAR(100)	Employee department

Your question is In-Memory SQL Database Task. Start with the requirements and the one table 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.

Problem

Output

Return one row per employee matching both conditions.
Include id, name, email, and department.
Sort by id ascending, preserving NULL values for omitted columns.

Schema

employees

Column	Type	Description
idPK	INT	Unique employee identifier
name	VARCHAR(100)	Employee name, which may be omitted
email	VARCHAR(255)	Employee email address
department	VARCHAR(100)	Employee department

Your question is In-Memory SQL Database Task. Start with the requirements and the one table 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.