Which SQL function can be used to count the number of rows in a GROUP BY clause?COUNT()SUM()AVG() MAX()

To count the number of rows in a GROUP BY clause, the SQL function that should be used is the COUNT() function.

Explanation

1. COUNT() Function: This function is specifically designed to count the number of rows that match a specific condition or to count the total rows in a result set. When used with GROUP BY, COUNT() will give the count of rows for each group.

2. Other Functions:

   • SUM(): This function adds up numeric values and is not used for counting rows.
   • AVG(): This function calculates the average value of a numeric column, also not related to counting rows.
   • MAX(): This function returns the maximum value from a set of values and does not count rows.

Conclusion

Therefore, the correct answer to the question is COUNT().