COUNT
The COUNT() function returns the number of records returned by a SELECT query.
caution
NULL values are not counted.
Syntax
COUNT(<expr>)
Arguments
Arguments | Description |
---|---|
<expr> | Any expression. This may be a column name, the result of another function, or a math operation. * is also allowed, to indicate pure row counting. |
Return Type
An integer.
Example
Create a Table and Insert Sample Data
CREATE TABLE students (
id INT,
name VARCHAR,
age INT,
grade FLOAT NULL
);
INSERT INTO students (id, name, age, grade)
VALUES (1, 'John', 21, 85),
(2, 'Emma', 22, NULL),
(3, 'Alice', 23, 90),
(4, 'Michael', 21, 88),
(5, 'Sophie', 22, 92);
Query Demo: Count Students with Valid Grades
SELECT COUNT(grade) AS count_valid_grades
FROM students;
Result
| count_valid_grades |
|--------------------|
| 4 |