Question

I am using the PHP function mysqli_query to run a SELECT query.

What does mysqli_query return if the query runs successfully, but the query finds no matches?

Answer 1

Per the manual:

Returns FALSE on failure. For successful SELECT, SHOW, DESCRIBE or EXPLAIN queries mysqli_query() will return a mysqli_result object. For other successful queries mysqli_query() will return TRUE.

A query that runs but returns no results is still considered a “successful query”, since the query did run in the database and an empty result set is a legitimate response. This means the query will still return a mysqli_result object, and if you check its row count (either via $result->num_rows in the object-oriented style or mysqli_num_rows($result) in the procedural style) it will return 0.