Finding out how mnay records are in a queryy

[tedpottel@gmail.com]

Hi,
Write now I have code to read in a set of data from a surrey. Could I
find out how many rows of data the query has, without adding to a
counter each time I read a row?

Also is there a way to start reading the database from a specific row,
instead of always starting at the begging?

This is what my code looks like


$sql="SELECT * FROM zen_products where 1";

if (!$results=mysq l_query($sql,$d blink))
die("<brcould not query database");


// can we figure out the size
// go to a spefic loction without looping?
while( $row=mysql_fetc h_array($result s))
{
extract($row);
echo "=id";
echo $products_id;
}

// close databse connection
mysql_close($db link);

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Re: Finding out how mnay records are in a queryy

tedpottel@gmail .com wrote:

Could I find out how many rows of data the query has, without adding to a
counter each time I read a row?

http://php.net/mysql_num_rows

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Iván Sánchez Ortega -ivan-algarroba-sanchezortega-punto-es-

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Re: Finding out how mnay records are in a queryy

On 3 Oct, 18:07, Iván Sánchez Ortega <ivansanchez-...@rroba-
escomposlinux.-.punto.-.orgwrote:

tedpot...@gmail .com wrote:

Could I find out how many rows of data the query has, without adding toa
counter each time I read a row?

>

http://php.net/mysql_num_rows

>

The mysql buffer lives outside the php memory limit - sometimes it may
be a good idea to get a count of rows without reading them in
So...

depending on your DBMS version:

$SQL="SELECT * FROM zen_products where 1"; // or whatever

$prev_rows=chec k_cached_count( $SQL);
if (!$prev_rows) {
$rows="SELECT COUNT(*) FROM ($SQL)";
$res=mysql_quer y($rows);
$data=mysql_fet ch_row($res);
$prev_rows=$dat a[0];
save_cache_data ($SQL, $prev_rows);
}
....

- this will still hurt the disk I/O on the DBMS though - hence the
caching.

MySQL allows you to first fetch the number of rows then retrieve rows
without hitting the datafiles again by using SQL_CALC_FOUND_ ROWS and
FOUND_ROWS() RTFM for more details.

C.