You can use mysqli::$affected_rows:
[php.net...]

In stored procedures and triggers, you can use ROW_COUNT():
[mariadb.com...]

You can use mysqli::$affected_rows:

This will return the number of rows in the result set, not the rows examined. As noted in the PHP docs, it "works like mysqli_num_rows() for SELECT statements."

I assume you're trying to avoid having to do a count of all rows in addition to the limited query. This has always felt inefficient to me as well (especially because a count can be very slow), but I've not yet found another way to do it, although in some cases it's possible and helpful (i.e. much faster) to store a count somewhere and update that when necessary. So if you're counting private messages, cache the number of messages and update it whenever a message is added or removed.

I think "examined rows" may also take into account any rows from joined tables, but I haven't checked.

I assume you're trying to avoid having to do a count of all rows in addition to the limited query.

Zackly :-/ There are several scripts where I find myself doing a second query just to get the count, and since the data is in the error log then it must exist somewhere! But I guess it's just not accessible to the user for some reason.

I've read too fast sorry.

But the number of examined rows is not what you're looking for. It's a number of rows internally read by MySQL while running the query, no matter if they're relevant or not. That information helps you find out why a query is slow, but it doesn't do what you want.

What you're looking for is SQL_CALC_FOUND_ROWS + FOUND_ROWS(), but it is deprecated in MySQL 8 (not in MariaDB):
[dev.mysql.com...]

Why did they deprecate it? Because it's a hack, and it's not more efficient than running two queries.