Multiplying rows

[Jon12345]

I have this segment of code:

echo "<td>".$row['kid']."</td>";
echo "<td>".$row['kidcount']."</td>";
echo "<td>".$row['count']."</td>";

I want to have another column where it takes the value in count and divides it by kidcount. i.e. count/kidcount. Then display this in another column.

How would I do that?

Thanks,

Jon

[bodzan]

You can add a new column like this:

if($row['kidcount']!=0){//to prevent division by 0
    echo "<td>".round($row['count']/$row['kidcount'],2)."</td>";//round result to two decimals
}
else{
    echo "<td>NA</td>";//the kidcount is 0
}

can't you???

[Jon12345]

Is there any way I can do it so that I can sort by the calculated row?

[bradgrafelman]

Try letting MySQL do the calculations:

SELECT ( `count` / `kidcount` ) AS newColumn, `kid`, `kidcount`, `count` ORDER BY `newColumn`

[Jon12345]

Would that cause a problem with divisions by zero?

[Piranha]

try it out and you will see

[bradgrafelman]

Piranha wrote:

try it out and you will see

Also, as per the MySQL docs:

By default, division by zero produces a result of NULL and no warning. With the ERROR_FOR_DIVISION_BY_ZERO SQL mode enabled, MySQL handles division by zero differently:

• If strict mode is not enabled, a warning occurs.

• If strict mode is enabled, inserts and updates involving division by zero are prohibited, and an error occurs.