Null Handling Basics — Solution & ExplanationProblems / Null Handling Basics / EditorialApproachNull handling is critical in real-world data.

COALESCE(email, 'no-email@placeholder.com') replaces NULL emails with a placeholder.

WHERE phone IS NOT NULL filters out rows with missing phone numbers.

COALESCE takes any number of arguments and returns the first non-null one. IS NULL / IS NOT NULL are the correct way to check for nulls — never use = NULL.Hints

COALESCE(value, default) returns the first non-null argument.

Use IS NOT NULL in the WHERE clause to exclude rows with missing values.

In PySpark, use F.coalesce() with F.lit() for the default value.

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