问题：
You define a multiple-row subquery in the WHERE cl
选项
The main query executes with the first value returned by the subquery.
The main query executes with the last value returned by the subquery.
The main query executes with all the values returned by the subquery.
The main query fails because the multiple-row subquery cannot be used with the comparison operator.√
You cannot define a multiple-row subquery in the WHERE clause of a SQL query.
答案：
D.The main query fails because the multiple-row subquery cannot be used with the comparison operator.