Most efficient way to dump entire mysql result set into an array?

Question

I am trying to put the entire results set into an array as follows:

while($myres[]=$result->fetch_array(MYSQLI_ASSOC));

This works ok but if I have 5 rows returns in my results the array has 6 index the last being null. So it seems that my array is always one index too big.

I could use num_rows to loop the results but this requires me setting up my own counter and incrementing it, I like the shorthand efficiency of my line above but how to stop it populating the last index with a null set.

This is an alternative to me using fetch_all which I discovered requires a special driver which not all php servers have installed.

Answer 1

I would just use multiple lines

$myres = array();
while ($row = $result->fetch_array(MYSQLI_ASSOC)) {
    $myres[] = $row;

However, if you have to have it without the extra array assignment line

while ($row = $result->fetch_array(MYSQLI_ASSOC) && $myres[] = $row) {

but that is more or less the same.

Answer 2

The expression

while($myres[]=$result->fetch_array(MYSQLI_ASSOC));

does the following:

1. execute $result->fetch_array(MYSQLI_ASSOC)
2. assign the result of this expression to $myres[] , thereby appending an entry to the $myres array
3. pass the result of $result->fetch_array(MYSQLI_ASSOC) as a condition to the while statement and determine whether the loop should be exited.

Notice that appending an entry to the $myres array happens before determining if the while loop should be exited. This is where your extra row comes from.

You will not lose any efficiency by doing it the classical way:

while ($record = $result->fetch_array(MYSQLI_ASSOC)) {
 $myres[] = $record; 
}