Question

I am creating a script that searches a database for abandoned carts and emails the contents to the customer (product name, image, quantity etc). The data is spread across a number of tables and as a far as getting the information and emailing it – so far so good. However it is sending one email per product that the customer has put in their cart. So if they have 5 items in their cart, it sends 5 emails. I know this is because of my join and while statement but my php/sql knowledge isn’t very good.

So my question is which join or union statement should I be using so that an email is only sent once to one customer containing all of their products.

The tutorials I’ve read about Joins always have 1 id or key that is common between all tables, however with the database structure of this store one table relates to another based off 1 key, and then that table uses a different key to relate to the other reliant table.

Database Structure Looks like This.

ORDERS:
|   orderid    |   ordstatus   |   ordqty   |  ordcustid   |
|--------------|---------------|------------|--------------|
|    12637     |       0       |      1     |        0     |
|    12636     |      11       |      1     |     3531     |
|    12635     |      11       |      2     |     4192     |

ORDERPRODUCTS:
|  ordprodname  |  ordprodqty  |  orderorderid  |  orderprodid   |
|---------------|--------------|----------------|----------------|
|   product1    |      1       |      12637     |      1206      |
|   product2    |      1       |      12636     |       193      |
|   product3    |      1       |      12635     |      1712      |
|   product4    |      1       |      12635     |      1576      |

CUSTOMERS:
|  customerid  |  customeremail    |  firstname  |
|--------------|-------------------|-------------|
|     3531     | [e-mail]   |  Customer1  |
|     4192     | [e-mail]   |  Customer2  |

PRODUCTIMAGE:
|  imageid  |  imageprodid  |   imagethumb     |
|-----------|---------------|------------------|
| Product1  |      1206     | file/path/1.jpg  |
| Product2  |       193     | file/path/2.jpg  |
| Product3  |      1712     | file/path/3.jpg  |
| Product4  |      1576     | file/path/4.jpg  |

So far my script looks like this:

mysql_select_db("cartmail", $con);

$result = mysql_query("SELECT * 
            FROM    orders
                ,   orderproducts
                ,   productimage
                ,   customers
            WHERE   orders.orderid              = orderproducts.orderorderid
            AND     orderproducts.orderprodid   = productimage.imageprodid
            AND     orders.ordcustid            = customers.customerid
            AND     ordstatus = '11'
            LIMIT 0 , 30");

while($row = mysql_fetch_array($result))
{
    <My PHP mail script...>
}

mysql_close($con);

Answer 1

Following query uses GROUP_CONCAT in MySQL to concatenate the product details in the order and provides single column value for each customer. The result set contains unique customer id, customer name, customer email along with with the concatenated list of their order details. Hopefully that gives you an idea to use the concatenated order information in the email body that will be sent to customers.

I don’t know PHP but the query should give you an idea on how to fetch the results.

Click here to view the demo in SQL fiddle.

Script:

CREATE TABLE orders
(
    orderid INT NOT NULL
  , orderstatus INT NOT NULL
  , ordqty INT NOT NULL
  , ordcustid INT NOT NULL
);

CREATE TABLE orderproducts
(
    ordprodname     VARCHAR(30) NOT NULL
  , ordprodqty      INT         NOT NULL
  , orderorderid    INT         NOT NULL
  , orderprodid     INT         NOT NULL
);

CREATE TABLE customers
(
    customerid      INT         NOT NULL
  , customeremail   VARCHAR(30) NOT NULL
  , firstname       VARCHAR(30) NOT NULL
);

CREATE TABLE productimage
(
    imageid         VARCHAR(30)     NOT NULL
  , imageprodid     INT             NOT NULL
  , imagethumb      VARCHAR(30)     NOT NULL
);

INSERT INTO orders (orderid, orderstatus, ordqty, ordcustid) VALUES
   (12637, 0,   1, 0),
   (12636, 11,  1, 3531),
   (12635, 11,  2, 4192);

INSERT INTO orderproducts (ordprodname, ordprodqty, 
            orderorderid, orderprodid) VALUES
   ('product1', 1, 12637, 1206),
   ('product2', 1, 12636, 193),
   ('product3', 1, 12635, 1712),
   ('product4', 1, 12635, 1576);

INSERT INTO customers (customerid, customeremail, firstname) VALUES
   (3531, '[e-mail]', 'Customer1'),
   (4192, '[e-mail]', 'Customer2'),
   (1111, '[e-mail]', 'Customer3');

INSERT INTO productimage (imageid, imageprodid, imagethumb) VALUES
   ('Product1', 1206,   'file/path/1.jpg'),
   ('Product2', 193,    'file/path/2.jpg'),
   ('Product3', 1712,   'file/path/3.jpg'),
   ('Product4', 1576,   'file/path/4.jpg');

SELECT          c.customerid
            ,   c.firstname
            ,   c.customeremail,
                group_concat('Order Id: ', orderid, 
                    ' | Product name: ', ordprodname, 
                    ' | Quantity: ', ordprodqty, '<br>') AS ordered_items,
FROM            customers c
LEFT OUTER JOIN orders o
ON              o.ordcustid = c.customerid
LEFT OUTER JOIN orderproducts op
ON              op.orderorderid = o.orderid
LEFT OUTER JOIN productimage pi
ON              pi.imageprodid = op.orderprodid
GROUP BY        c.customerid
HAVING          COUNT(DISTINCT o.ordcustid) > 0;

Output:

CUSTOMERID FIRSTNAME   CUSTOMEREMAIL     ORDERED_ITEMS
---------- ----------- ----------------  ------------------------------------
3531       Customer1   [e-mail]   Order Id: 12636 | Product name: product2 | Quantity: 1<br>
4192       Customer2   [e-mail]   Order Id: 12635 | Product name: product4 | Quantity: 1<br>,
                                         Order Id: 12635 | Product name: product3 | Quantity: 1<br>