What is count () in SQL?

What is count in SQL query?

SQL Server COUNT() Function The COUNT() function returns the number of records returned by a select query. Note: NULL values are not counted.

What is difference between count (*) and count () in SQL?

The simple answer is no – there is no difference at all. The COUNT(*) function counts the total rows in the table, including the NULL values.

Why count is used in SQL?

The COUNT() function is one of the most useful aggregate functions in SQL. Counting the total number of orders by a customer in the last few days, the number of unique visitors who bought a museum ticket, or the number of employees in a department, can all be done using the COUNT() function.

Why do we use count (*)?

The COUNT(*) function counts all the rows from Person. Person table. When we use an expression in the COUNT(Middlename), this returns the number of rows with a MiddleName value that is not null. In this case, the COUNT doesn't include null values in its total.