SQL Division and NULL Behavior | Dataford Interview Questions

Virtusa Data Platform runs SQL expression checks before deploying transformations. Write a PostgreSQL query that reports the outcome of four division expressions: 0 / NULL, NULL / 1, NULL / NULL, and 0 / 0.

The query must classify division by zero without executing an unsafe expression that would abort the statement.

Requirements

Return only the four requested expression cases.
Join each expression to its runtime profile.
Return the expression label, operands, evaluated result, and status.
Represent divisions involving NULL as a NULL result, and represent 0 / 0 as a division-by-zero error status.
Order results in the requested expression order.

Schema

expression_cases

Column	Type	Description
case_idPK	INT	Unique expression test identifier
profile_id	INT	Referenced runtime profile
expression_label	VARCHAR(40)	Human-readable arithmetic expression
numerator	NUMERIC	Left operand of the division
denominator	NUMERIC	Right operand of the division
display_order	INT	Ordering of the expression in the report

runtime_profiles

Column	Type	Description
profile_idPK	INT	Unique runtime profile identifier
profile_name	VARCHAR(50)	Name of the execution profile
active	BOOLEAN	Whether the profile is currently active

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