How to Efficiently Count MySQL Rows Using SELECT COUNT(*) with PHP?

*PHP and MySQL SELECT COUNT() efficiently count the number of rows**

In MySQL database operations, obtaining only the number of table rows instead of all rows or specific column data can significantly improve efficiency. SELECT COUNT(*) Query statements are born for this purpose.

Query usage

SELECT COUNT(*) in SQL is used to count the number of table rows. * represents all rows, indicating that all rows need to be counted. It is not recommended to specify the column name after the COUNT keyword, but give the count result an alias.

Example:

$mysqli->query("SELECT COUNT(*) AS cnt FROM cars");

In this example, cnt is the alias of the counting result.

Get counting results in PHP

After executing the query, you need to obtain the counting results in the PHP script. Since the query returns a scalar value, you can use the fetch_object() method and then access the cnt attribute to get the count.

Example:

$count = $mysqli->query("SELECT COUNT(*) AS cnt FROM cars")->fetch_object()->cnt;

This code assigns the counting result to the $count variable to facilitate subsequent code use.

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