Multiple choice technology programming languages

COUNT (DISTINCT expr) returns

  1. No. of rows in a table

  2. No. of rows with non-null values of the expr

  3. No. of distinct non-null values of the expr

  4. . None of the above
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C Correct answer
Explanation

The COUNT(DISTINCT expr) function evaluates the expression for each row, filters out duplicate values and null values, and returns the total count of the remaining unique, non-null values. Options claiming it counts all rows or all non-null values (including duplicates) are incorrect.

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