php while and for loops to fill array not working

Question

I have a Product master in which I have 2 fields, ONE is for Main Product (Field name 'Under') and SECOND is for Sub-product (Field name is 'Prod_desc) What I want is a nested loop where I capture all codes (field name is Cylno) from transaction Table (ECR_CBDC).

I have 2 nested loops, First while loop is for PRODUCT_MASTER where based on user selection of a Main-product the sub-products are selected and SECOND loop is for collecting the codes for all sub-products.

Now the issue is it collects only 1 value as the FOR loop overwrites the previous value. Is there any other loop which can hold the previous value of each sub-product.

$p=mysql_query("SELECT * FROM PRODMAST WHERE Under='$product'");
while ($p2=mysql_fetch_assoc($p))
{
    $prodesc=$p2['Prod_desc'];

    $dc=mysql_query("SELECT * FROM ECR_CBDC WHERE Prod_desc='$prodesc'  AND usr='$user'");
    $num_rows = mysql_num_rows($dc);
    $fill_from_array = array(); /* as "value"=>"option" */
    for($i = 1; $i <= $num_rows; $i++)
    {
        $row = mysql_fetch_assoc($dc);
        $fill_from_array[$row['Cylno']] = $row['Cylno'];
    }
}

Maccath · Accepted Answer · 2012-11-15 09:47:23Z

1

If I understand what you're asking - $fill_from_array only collects one row's worth - I think you need to define $fill_from_array outside of the first loop, so...

$p=mysql_query("SELECT * FROM PRODMAST WHERE Under='$product'");
$fill_from_array = array(); /* as "value"=>"option" */
while ($p2=mysql_fetch_assoc($p))
{
    $prodesc=$p2['Prod_desc'];

    $dc=mysql_query("SELECT * FROM ECR_CBDC WHERE Prod_desc='$prodesc'  AND usr='$user'");
    $num_rows = mysql_num_rows($dc);
    for($i = 1; $i <= $num_rows; $i++)
    {
        $row = mysql_fetch_assoc($dc);
        $fill_from_array[$row['Cylno']] = $row['Cylno'];
    }
}

That way it's not over-writing $fill_from_array each time the while() loop loops. Is that what you mean?

answered Nov 15, 2012 at 9:47

Maccath

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Ja͢ck · Accepted Answer · 2012-11-15 09:59:59Z

1

Instead of emulating a join in code, use the JOIN syntax instead to reduce the number of loops and data transfer:

SELECT * FROM PRODMAST 
INNER JOIN ECR_CBDC ON PRODMAST.Prod_desc=ECR_CBDC.Prod_desc AND usr='$user'
WHERE Under='$product'

answered Nov 15, 2012 at 9:59

Ja͢ck

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2 Comments

Ja͢ck Over a year ago

@user1387008 As your data set grows, this solution will become much faster than having two loops; just something to keep in mind.

Ja͢ck Over a year ago

@user1387008 Since you're new to SO ... if the answer is useful you should upvote it (you have enough rep for it now).

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