How can I loop through a MySQL result set more than once using the mysql_* functions?

For whatever reason, I need to go through a MySQL result set twice. Is there a way to do it?

I don't want to run the query twice and I don't want to have to rewrite the script so t开发者_如何学编程hat it stores the rows somewhere and then reuses them later.

This is how you can do it:

$result = mysql_query(/* Your query */);
while($row = mysql_fetch_assoc($result)){
 // do whatever here...
}

// set the pointer back to the beginning
mysql_data_seek($result, 0);
while($row = mysql_fetch_assoc($result)){
 // do whatever here...
}

However, I would have to say, this doesn't seem the right way to handle this. Why not do the processing within the first loop?

For mysqli you should do the following;

$result= $con->query($sql); // $con is the connection object
$result->data_seek(0); 

Try whether mysql_data_seek() does what you need.

mysql_data_seek() moves the internal row pointer of the MySQL result associated with the specified result identifier to point to the specified row number. The next call to a MySQL fetch function, such as mysql_fetch_assoc(), would return that row.

row_number starts at 0. The row_number should be a value in the range from 0 to mysql_num_rows() - 1. However if the result set is empty (mysql_num_rows() == 0), a seek to 0 will fail with a E_WARNING and mysql_data_seek() will return FALSE

Alternative to the data seek is to store the values into an array:

$arrayVals = array();
$result = mysql_query(/* Your query */);
while($row = mysql_fetch_assoc($result)){
    $arrayVals[] = $row;
}

// Now loop over the array twice instead

$len = count($arrayVals);
for($x = 0; $x < $len; $x++) {
    $row = $arrayVals[$x];

    // Do something here    
}

$len = count($arrayVals);
for($x = 0; $x < $len; $x++) {
    $row = $arrayVals[$x];

    // Do something else here   
}

I confess I haven't tried this, but have you tried after your first iteration

mysql_data_seek($queryresult,0);

to go to the first record?

You can use mysql_data_seek to move the internal pointer to the beginning of the data set. Then, you can just iterate through it again.

Well, you could always count the number of rows you read, and then do something like this:

if (rownumber == mysql_num_rows($result)) { mysql_data_seek($result, 0); }

Don't know why you would need to, but there it is.