Multiple choice technology databases

Why one should NOT use expressions on the columns in the predicate?

  1. Optimizer will return parse error if expressions are used on columns in the predicate

  2. Optimizer does not use index if expressions are used on the columns in the predicate, even if one exists

  3. It makes no difference with / without expressions on the columns in the predicate

  4. Using expressions on the columns in the predicate won't get benefits of using Table Alias
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B Correct answer
Explanation

When you apply functions or expressions to indexed columns in WHERE clauses (e.g., WHERE UPPER(name) = 'TEST'), the optimizer cannot use the index on that column. This forces a full table scan instead of an efficient index range scan, severely degrading performance.

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