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Identify and remove duplicate records from a table, keeping the most recent record based on a timestamp column.

SQLmedium0.6 min readPremium

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119 wordsInterview-ready

To remove duplicates keeping the most recent by timestamp: WITH ranked AS (SELECT *, ROW_NUMBER() OVER (PARTITION BY key_columns ORDER BY timestamp_col DESC) rn FROM table_name) DELETE FROM table_name WHERE (key_columns, timestamp_col) IN (SELECT key_columns, timestamp_col FROM ranked WHERE rn > 1). Or create a new table: CREATE TABLE deduped AS SELECT * FROM (SELECT *, ROW_NUMBER() OVER (PARTITION BY id ORDER BY updated_at DESC) rn FROM raw) t WHERE rn=1....

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