better way to counting result and read row in php - php

Question

the first, my current code is
$sql = "SELECT COUNT(id) AS total FROM mytable WHERE something = ".$likethis;
$query = mysqli_query($connection, $sql);
$result = mysqli_fetch_object($query);
if the result give 1 or more data, then i do this query to get the data
$sql = "SELECT col1, col2, col3 FROM mytable WHERE something = ".$likethis;
the second one, another method i found is using this code
$totalRow = mysqli_num_rows($query);
then if give 1 or more, i do fetch the data.
in my head now is, the first one is fast on counting data then only do the rest if have result. but need connect to database twice.
the second one is slower because need to read all data but only connect to database once.
i'm not sure my opinion is accurate it just by how much php read database, and not sure actually which one is better.
or maybe there are other better way to do:
- check how much row it have
- get the rows if have

Answer 1

You can set flag for check you can get row/rows or not. If you can't get any row from database flag is true.
For e.g.
$query = mysqli_query($connection,"select * from `test`");
$flag = true;
while($rows = mysqli_fetch_array($query)){
$flag = false;
// Do stuff.
}
if($flag){
echo "No record found.";
}
If can not get results code will print else part.