![]() ![]() GROUP BY productLine Code language: SQL (Structured Query Language) ( sql ) The COUNT(*) function is often used with a GROUP BY clause to return the number of elements in each group.įor example, this statement uses the COUNT() function with the GROUP BY clause to return the number of products in each product line: SELECT We’ll use the products table from the sample database for the next examples: A) Using MySQL COUNT(*) function with a GROUP BY example This example uses COUNT(DISTINCT expression) to count non-NULL and distinct values in the column val: SELECT COUNT( DISTINCT val)įROM count_demos Code language: SQL (Structured Query Language) ( sql ) MySQL COUNT() function practical examples Notice that two NULL values are not included in the result. ![]() If you specify the val column in the COUNT() function, the COUNT() function will count only rows with non-NULL values in the val column: SELECT COUNT(val)įROM count_demos Code language: SQL (Structured Query Language) ( sql ) WHERE val = 2 Code language: SQL (Structured Query Language) ( sql ) MySQL COUNT(expression) example This example uses the COUNT(*) function with a WHERE clause to specify a condition to count only rows whose value in the column val is 2: SELECT COUNT(*) The following statement uses the COUNT(*) function to return all rows from the count_demos table: SELECT COUNT(*) FROM count_demos Code language: SQL (Structured Query Language) ( sql ) Third, query data from the count_demos table: SELECT * FROM count_demos Code language: SQL (Structured Query Language) ( sql ) MySQL COUNT(*) example Second, insert some rows into the count_demos table: INSERT INTO count_demos(val) ) Code language: SQL (Structured Query Language) ( sql ) MySQL COUNT() function illustration Setting up a sample tableįirst, create a table called count_demos: CREATE TABLE count_demos ( The COUNT() function returns 0 if there is no matching row found. The return type of the COUNT() function is BIGINT. The COUNT(DISTINCT expression) returns the number of distinct rows that do not contain NULL values as the result of the expression. The COUNT(expression) returns the number of rows that do not contain NULL values as the result of the expression. The COUNT(*) returns the number of rows including duplicate, non-NULL and NULL rows. ![]() The COUNT(*) function returns the number of rows in a result set returned by a SELECT statement. The COUNT() function has three forms: COUNT(*), COUNT(expression) and COUNT(DISTINCT expression). The COUNT() function allows you to count all rows or only rows that match a specified condition. The COUNT() function is an aggregate function that returns the number of rows in a table. Introduction to the MySQL COUNT() function Summary: in this tutorial, you will learn how to use the MySQL COUNT() function to return the number rows in a table. ![]()
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