In PHP, the max() function and the count() function are two very commonly used built-in functions, each of which has clear uses. This article will explore whether they can be used in combination and introduce common uses of these two functions.

We can use PDOStatement::rowCount() and SELECT COUNT() to get the number of rows of the query result. Although the two look similar, they have different working mechanisms, application scenarios, performance performance and usage methods. Understanding the difference between them is crucial for developers to write efficient database queries.