while循环与赋值运算符

I can't seem to figure out how this loop works in PHP:

$people = array();
while($row = $result->fetch_assoc())
    $people[] = $row;

It seems as though the loop would just keep going, infinitely. But, it doesn't How exactly does this work? Can someone explain it to me step-by-step? I'm guessing that the while loop could also be written like this:

while(($row = $result->fetch_assoc()) == true)

The fetch_assoc fetches one result row at a time and stores it in $row. Since this is in a loop, you are fetching until you run out of rows

In the loop you are essentially pushing the $row value into a $people array

fetch_assoc will return false either upon an error or when the cursor for the fetch hits the end of all the rows and no more rows can be fetched, so it will return false.

Every time you fetch for the query, a cursor keeps track of the last returned row and will continue to keep track ultimately till you finish reading all rows.

Edit: Sorry I was thinking about PDO and not mysqli, however it should be about the same thing.

Your code:

$people = array();
while($row = $result->fetch_assoc())
   $people[] = $row;

Example how its works (MySQL):

$people = array();
$result = mysql_query($query);
$rows_count = mysql_num_rows($result);
for ($i = $rows_count - 1; $i >= 0; $i--) {
   mysql_data_seek($result, $i);
   $people[] = mysql_fetch_assoc($result);
}

How U see first option is more compact.