Excel Lookup Logic in SQL | Dataford Interview Questions

Your question is Excel Lookup Logic in SQL. Take a moment with it on the right.

Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).

Problem

Context

Analysts often use VLOOKUP or XLOOKUP in Excel to pull values from one table into another. In SQL, the equivalent idea is usually implemented with joins rather than spreadsheet formulas.

Core Question

Explain how you would translate VLOOKUP or XLOOKUP logic into SQL. In your answer, cover:

Which SQL operation is the closest equivalent
The difference between returning only matched rows versus keeping all rows from the main table
How to handle missing matches
Why SQL is often better than spreadsheet lookups for larger datasets

Scope Guidance

The interviewer expects a practical conceptual explanation, not just a definition. You should describe the SQL pattern, compare it to Excel behavior, and give short PostgreSQL examples showing how lookup logic works in real tables.

Your question is Excel Lookup Logic in SQL. Take a moment with it on the right.

Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).

Context

Analysts often use VLOOKUP or XLOOKUP in Excel to pull values from one table into another. In SQL, the equivalent idea is usually implemented with joins rather than spreadsheet formulas.

Core Question

Explain how you would translate VLOOKUP or XLOOKUP logic into SQL. In your answer, cover:

Which SQL operation is the closest equivalent
The difference between returning only matched rows versus keeping all rows from the main table
How to handle missing matches
Why SQL is often better than spreadsheet lookups for larger datasets