2-Sum SQL with Repeated Values | Dataford Interview Questions

Write a SQL query to solve a classic 2-sum problem on a dataset with repeated values.

Treat each row as a distinct element, so equal numeric values from different rows may form a valid pair. Return every pair of distinct rows whose values sum to a target, excluding null values and targets without a matching pair.

Output

One row per matching pair and target
Columns: target_value, first_value_id, second_value_id, first_value, second_value
Order by target_value, then first_value_id, then second_value_id ascending

Schema

two_sum_values

Column	Type	Description
value_idPK	INT	Unique identifier for an input row
number_value	INT	Numeric value used in pair calculations

two_sum_targets

Column	Type	Description
target_idPK	INT	Unique identifier for a target
target_value	INT	Required sum for a matching pair

Your question is 2-Sum SQL with Repeated Values. Start with the requirements and the two tables 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