What changes the condition in loop: while (mysql_fetch_array($var))?

Question

I'm a beginner C programmer. I recently started learning PHP and MySQL and encountered this interesting behavior with while loop:

while ($pages = mysql_fetch_array($pages_set))
    {statement}

I previously learned that condition must be changed somewhere in the loop (or in the expression itself) in order for the loop to be finite, but in this case i just can't see it.

I researched a bit about mysql_fetch_array() function and found this:

Returns an array that corresponds to the fetched row and moves the internal data pointer ahead.

Is it true to say that the pointer moves through the row and when it reaches the end it will return 0 or NULL?

since you're just learning PHP, it's worth pointing out that the mysql_xxx() functions are deprecated. You should use either the mysqli_xxx() alternatives or the PDO library instead. See the PHP manual for more info. However, with either of these libraries, similar constructs are possible, so your question is still relevant. — Spudley
– Spudley, Commented Jul 31, 2012 at 19:46

Ynhockey · Accepted Answer · 2012-07-31 11:13:27Z

4

The pointer moves to the next row in the recordset with each iteration, so that when there is no data left then $pages will be NULL and the loop will end.

answered Jul 31, 2012 at 11:13

Ynhockey

3,9515 gold badges37 silver badges55 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

What changes the condition in loop: while (mysql_fetch_array($var))?

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related