Question

How can i display variable only once in the table.

<?php
$sql = mysql_query("SELECT * FROM babydata");
while ($row = mysql_fetch_array($sql)) {
    for ($i = 1; $i <= 72; $i++) {
        if ($i == $weeknumber) {
            echo "<tr><td width='40'>Week $i</td>";
            echo "<td width='500' >" . count($row[$menucompare]) . "</td></tr>";
        }
    }
}
?>

this code display like this:

--------------
week4 |  1
-------------
week4 |  1
-------------

But i want to display weeknumber only once and count($row[$menucompare]) will be counted 2 in week 4 . not 1 and 1 .

Like this:

--------------
week4 | 2
---------------

Answer 1

Seems like you want to output the amount of tuples in babydata for a certain week. You can just filter out any tuples which dont belohnt to the $weeknumber in your query.

// TODO: Assert, that $weeknumber is an integer, to not be prune to SQL injection.
$weeknumber = (int)(($currentdate - $birthday) / (7 * 24 * 60 * 60)) + 1;

// Select the amount of tuples in babydata for the desired $weeknumber.
$result = mysql_query("SELECT count(*) FROM babydata ".
    "WHERE week = $weeknumber");

// There is only one tuple with one column that contains the amount as number. 
$row = mysql_fetch_row($result);

// Output the week and the amount of data.
echo "<tr><td width='40'>Week $weeknumber</td>" ;
echo "<td width='500' >".$row[0]."</td></tr>";

No need for loops.

To output all weeks and their respective amount of data:

// Select the amount of tuples in babydata for all weeks.
$result = mysql_query("SELECT week, count(*) FROM babydata ".
    "GROUP BY week");

// For all weeks:
while ($row = mysql_fetch_row($result))
{
    // Output the week and the amount of data.
    echo "<tr><td width='40'>Week ".$row[0]."</td>" ;
    echo "<td width='500' >".$row[1]."</td></tr>";
}

This assumes that you have a column week in your table babydata that contains just a number. This outputs only weeks, that have at least one tuple.