COUNT()

The COUNT() aggregate function returns the total number of rows that match the specified criteria.

SELECT COUNT(column_name)
FROM table_name;

COUNT() is a function that takes the name of a column as an argument and counts the number of rows where the column is not NULL.

Note: A column name of the table can also be used instead of *. Unlike COUNT(*), this variation COUNT(column_name) will not count NULL values in that column.

Suppose there’s an employees table with the following values:

To find the total number of employees who have less than 5 years of experience, the given query can be used:

SELECT COUNT(*)
FROM employees
WHERE experience < 5;

The result would be: