Multiple choice technology databases

SQL statement with “High Selectivity” means

  1. No. of rows returned by SQL statement are HIGH

  2. No. of rows returned by SQL statement are FEW

  3. No. of rows returned by SQL statement are > 10000

  4. No. of rows returned by SQL statement are > 50000
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B Correct answer
Explanation

High selectivity in SQL means the query predicate filters out most rows, returning only a FEW rows from the table. Selectivity is the ratio of rows returned to total rows - high selectivity means a small ratio (few rows), which is good for index usage. Low selectivity means many rows are returned, often making full table scans more efficient.

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