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Home/Questions/SQL/How would you handle null values in a dataset, especially in a single column?

How would you handle null values in a dataset, especially in a single column?

SQLeasy0.7 min readPremium

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135 wordsInterview-ready

Handling null values depends on business context. Options: (1) Fill with default—COALESCE(column, 0) for numeric, COALESCE(column, 'Unknown') for strings; (2) Forward/backward fill for time-series—LAG/LEAD or pandas ffill/bfill; (3) Impute (mean, median, mode) for ML pipelines; (4) Exclude—WHERE column IS NOT NULL when nulls are invalid; (5) Treat as separate category—CASE WHEN column IS NULL THEN 'Missing' ELSE column END....

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