mysql - PHP Counting Number of Rows -


i have following code used echo number of columns accident , wanted count rows i've changed not echoing anything. ideas? way have connected database though not shown.

<p> <?php $result = mysqli_query("select * user_info"); $num_rows = mysqli_num_rows($result); echo $num_rows[0];  mysqli_close($con); ?>  records in our database start search <a href="#">here</a> today.  </p>

as general rule, should minimize traffic between db server , application server.

for specific case, means recommended way of "counting" is:

<?php $result = mysqli_query("select count(*) user_info"); $row = mysqli_fetch_row($result); $num = $row[0]; ?>

with request (select count(*) ...), db server count rows you. , return total -- possibly using indexes or internal data structure return directly result. select *, server has retrieve , send data in table. quite expensive , rather inefficient since don't use these data after in application...

edit -- if want "simple" explanation: efficient know number of pages in book? count them 1 one, or @ page numbers in footer?

with initial solution (counting in php), making xerox of book, , counting pages in copy. count(*) let db server use page numbers or index (the "toc" of book) find result.


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