Multiple choice technology programming languages

Which of the following operator when used with numbers is not efficient ?

  1. NOT >

  2. NOT <

  3. NOT =

  4. None of the above
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C Correct answer
Explanation

The NOT = operator (meaning !=) is less efficient than direct comparison operators. When you use NOT =, the database must evaluate the condition and then negate the result, requiring two operations. Direct comparison operators like =, <, > evaluate in a single operation. NOT > and NOT < have similar inefficiency, but NOT = is specifically singled out as the least efficient.

AI explanation

The 'not equal' operator (NOT =, typically written as <> or !=) is generally the least efficient of comparison operators when applied to numeric columns in a database context, because it can't be satisfied by a simple range scan on an index — the optimizer typically has to scan most or all rows to find non-matching values, whereas NOT > and NOT < are logically equivalent to <= and >= respectively, which map cleanly onto ordered index range scans. This makes inequality checks (<>) a classic case where indexes provide little to no benefit, unlike range-based comparisons.

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