Question

Let’s say my resulting recordset is as follows:

Emp_ID    ID    Ability    Rating
------    --    -------    ------
NULL      DRI   Driving    NULL
NULL      TYP   Typing     NULL
NULL      GRA   Graphics   NULL
NULL      VID   Video      NULL
NULL      GAM   Gaming     NULL

while another case could be:

Emp_ID    ID    Ability    Rating
------    --    -------    ------
15        DRI   Driving    7
15        TYP   Typing     6
15        GRA   Graphics   8
15        VID   Video      7
15        GAM   Gaming     10

or:

Emp_ID    ID    Ability    Rating
------    --    -------    ------
22        DRI   Driving    4
NULL      TYP   Typing     NULL
NULL      GRA   Graphics   NULL
22        VID   Video      8
22        GAM   Gaming     5

What’s my least costly way in PHP to check if Emp_ID is all NULL like the first one?

Emp_ID is BIGINT(20) UNSIGNED (and Rating is TINYINT(2) UNSIGNED) in MySQL. The recordset is returned by $wpdb_custom->get_results().

Answer 1

$all_null = true;
foreach($wpdb->get_results() as $row) {
    if(!is_null($row['Emp_ID'])) {
        $all_null = false;
        break;
    }
}

Since you can’t edit the query, the best you can do is just iterate over the results checking for null. But the important thing is to break when you find a non-null row. At that point you know that not all rows are null, so don’t bother iterating over the remaining rows.