for($i=0;$i<$rownum;$i++)

[Miss-Ruth]

I need this script to go through each row of the mysql db and update the cat_num colum (for each record) with the new value. But this doen't seem to work. 

 

$marks = '25'; // this value is ever changing. For this example I'll put as 25

$query=mysql_query("SELECT * FROM table1");
$rownum=mysql_num_rows($query);
for($i=0;$i<$rownum;$i++)
{
    $query=mysql_query("SELECT * FROM table1 LIMIT $i,1");
    while($select=mysql_fetch_array($query))
    {
         $update=mysql_query("UPDATE table2 SET cat_num='$select[cat_num]'+$marks");
    }
}

[priti]

$query=mysql_query("SELECT * FROM table1");

$rownum=mysql_num_rows($query); // you are fetching all records from table1

 

for($i=0;$i<$rownum;$i++)

{

    $query=mysql_query("SELECT * FROM table1 LIMIT $i,1"); //why this is required here? you already fetched records from table1

    while($select=mysql_fetch_array($query))

    {

        $update=mysql_query("UPDATE table2 SET cat_num='$select[cat_num]'+$marks"); // print the update query

    }

}

[litebearer]

Close...

This only gets the number of records that meet the query

$rownum=mysql_num_rows($query);

BTW your update (because you have not limited it ie WHERE something = something ) will result is ALL records in table2 being set to the same value

 

[MMDE]

$marks = '25'; // this value is ever changing. For this example I'll put as 25

$query='SELECT * FROM table1';
$result=mysql_query($query);
while($row=mysql_fetch_array($result)){
mysql_query('UPDATE table2 SET cat_num='.$row[cat_num]+$marks);
}

You may want to put the query string inside the actual mysql_query function, but don't be tempted to put the mysql_query inside the mysql_fetch_array while loop. It will then loop get a new mysql_query function each time, infinite, unless there is some remove query.

 

I don't see why you need 25..., do you need to do it max 25 times?

Because if so, just put a check at the end after the update query:

$marks--;
if($marks==0){
break;
}

 

 

$rownum=mysql_num_rows($query);

I see why you want to use the number of rows, but I don't see why you actually need it...