Question

Table1: id, cr_id 
10 | 81
10 | 82

Table2: cr_id, name
80 | Title80
81 | Title81
82 | Title82
83 | Title83

I have two mysql queries for them (getting results with mysql_fetch_array()). I’m doing a html select box, in which some values will be selected.

How to compare strings cr_id.Table1 and cr_id.Table2 without using mysql query?

Upd. I want to achieve a php function which will return “selected” if cr_id.Table1==ccr_id.Table2 and Null if the not.

Upd2. What’s wrong?

function checked($result_creative, $result_creative_chkd) {
                $select_row = null;
                if( strcmp( $result_creative['creative_id'], $result_creative_chkd['creative_id']) == 0)
                    {
                        $select_row = 'selected';
                    }
                };

            $query_creative_chkd=mysql_query("SELECT * FROM s_s_creative WHERE $id=id");
            $creative_chkd=mysql_num_rows($query_creative_chkd);
                if($creative_chkd != 0) 
                    {
                        while ($result_creative_chkd = mysql_fetch_array($query_creative_chkd)) 
                        {
                        $creative_s_id_chkd = $result_creative_chkd['id'];
                        $creative_id_chkd = $result_creative_chkd['creative_id'];
                        }
                    };

            $query_creative=mysql_query("SELECT * FROM s_creative ORDER BY creative_id ASC");
            $numrows_creative=mysql_num_rows($query_creative);
                if($numrows_creative != 0) 
                    {
                    while ($result_creative = mysql_fetch_array($query_creative)) 
                        {
                        $creative_id = $result_creative['creative_id'];
                        $creative_name = $result_creative['name'];

                        $select_row = checked($result_creative, $result_creative_chkd);

                        echo "<option value=\"".$creative_id."\" ". $select_row ." >".$creative_name."</option>\n  ";   
                        }
                    } 

Answer 1

You can use the comparison operator:

if( $row['cr_id'] == $row2['cr_id'])

OR, use the case sensitive string compare function strcmp

if( strcmp( $row['cr_id'], $row2['cr_id']) == 0)

OR, use the case insensitive string compare function strcasecmp

if( strcasecmp( $row['cr_id'], $row2['cr_id']) == 0)

Edit:

Upd. I want to achieve a php function which will return “selected” if
cr_id.Table1==ccr_id.Table2 and Null if the not.

You can use any of the above methods to check if the two strings are equal, and set your variable appropriately. E.g.

// Case sensitive string compare:
$selected = null;
if( strcmp( $row['cr_id'], $row2['cr_id']) == 0)
{
    $selected = 'selected';
}

Edit: You have an error with your function (it’s not returning anything). Try this:

function checked( $result_creative, $result_creative_chkd) 
{    
    return ( strcmp( $result_creative['creative_id'], $result_creative_chkd['creative_id']) == 0) ? 'selected' : null;
}