Escaping single quote in PHP when inserting into MySQL

I have a perplexing issue that I can't seem to comprehend... I have two SQL statements: - The first enters information from a form into the database. - The second takes data from the database entered above, sends an email, and then logs the details of the transaction The problem is that it appears that a single quote is triggering a MySQL error on the second entry only! The first instance works without issue, but the second instance triggers the `mysql_error()`. Does the data from a form get handled differently from the data captured in a form? Query 1 - This works without issue (and without escaping the single quote) $result = mysql_query("INSERT INTO job_log (order_id, supplier_id, category_id, service_id, qty_ordered, customer_id, user_id, salesperson_ref, booking_ref, booking_name, address, suburb, postcode, state_id, region_id, email, phone, phone2, mobile, delivery_date, stock_taken, special_instructions, cost_price, cost_price_gst, sell_price, sell_price_gst, ext_sell_price, retail_customer, created, modified, log_status_id) VALUES ('$order_id', '$supplier_id', '$category_id', '{$value['id']}', '{$value['qty']}', '$customer_id', '$user_id', '$salesperson_ref', '$booking_ref', '$booking_name', '$address', '$suburb', '$postcode', '$state_id', '$region_id', '$email', '$phone', '$phone2', '$mobile', STR_TO_DATE('$delivery_date', '%d/%m/%Y'), '$stock_taken', '$special_instructions', '$cost_price', '$cost_price_gst', '$sell_price', '$sell_price_gst', '$ext_sell_price', '$retail_customer', '".date('Y-m-d H:i:s', time())."', '".date('Y-m-d H:i:s', time())."', '1')"); Query 2 - This fails when entering a name with a single quote (for example, *O'Brien*) $query = mysql_query("INSERT INTO message_log (order_id, timestamp, message_type, email_from, supplier_id, primary_contact, secondary_contact, subject, message_content, status) VALUES ('$order_id', '".date('Y-m-d H:i:s', time())."', '$email', '$from', '$row->supplier_id', '$row->primary_email' ,'$row->secondary_email', '$subject', '$message_content', '1')");