php mysql使用join从2个表中显示/获取由ORDER_DATE分组的客户订购的所有产品

Question

I have these two tables CART and ORDERS . I would like to display/get all the products ordered by the customer grouped by ORDER_DATE how can I do this by Joining these two table? or what is the correct code, script or syntax for it.. This is a 1:n relation I also want to display the items ordered by the customer ORDERED BY order_date..

CART Table:

• cart_id
• product_id
• user_id
• prod_name
• price
• quantity
• image

ORDER Table:

• order_id
• cart_id
• user_id
• total
• customer_name
• order_date

Answer 1

in case you are looking to list all the items by order date (not grouped) then it would be like this:

SELECT * 
FROM `order` 
LEFT JOIN cart ON cart.cart_id=`order`.cart_id 
ORDER BY order_date ASC

or :

SELECT * 
FROM cart 
LEFT JOIN `order` ON `order`.cart_id=cart.cart_id
ORDER BY order_date ASC

as from the structure it seems that cart can contain several orders (while order can not contain more carts) - that's where you must tell us, whether it is 1:n relation (of those two tables) or whether it's 1:1 (in which case you do not need the cart_id and can use the order_id instead as the linking element in both tables)

in case you want to "group" it somewhat, then you will have to sacrifice the detail (which is to be grouped together) grouping is useful, if you wanted to see the total values of all the orders - but doing so, you would only see the total value but NOT the items from each order (not in a line by line view)

[ sorry i forgot.. it's a 1:n relation.. i also need to display the ordered items from each customer.. is that possible ? :) ]

in that case the structure does not seem very sound assuming the master table is the "order" then the table with detail should contain refference to the master table:

CART Table:

• cart_id
• order_id ^(added)
• product_id
• user_id
• prod_name
• price
• quantity
• image

ORDER Table:

• order_id
• cart_id ^(removed)
• user_id
• total
• customer_name
• order_date

Again your question isn't very clear. Do you want to see the items a user purchased grouped by the items (that is, if they buy a pencil today rubber tomorrow and another pencil the day after tomorrow, you will see two lines of result similar to:

item   | qty
-------+----
pencil | 2  
rubber | 1

then use:

SELECT `order`.*, product_id, product_name, SUM(quantity) AS qty 
FROM `order` 
LEFT JOIN cart ON cart.order_id=`order`.order_id
GROUP BY product_id
ORDER BY product_name

Answer 2

Juan, this i getting really long and i'm not sure whether the Stack Overflow site is intended for this kind of dialog, but i'll try to explain once again. I will simplify your tables so the code i post here is simple.

CREATE TABLE orders (
    orderID int unsigned not null auto_increment,
    user int unsigned not null,
    PRIMARY KEY (orderID)
);

CREATE TABLE orderitems (
    oiID int unsigned not null auto_increment,
    order int unsigned not null,
    item int unsigned not null,
    PRIMARY KEY (oiID)
);

The above is assuming that there is a table of users (Where is the user's name and email etc) and table of items (where the item names and item prices are).

I'm also assuming (wrongly, but for the sake of simplicity), that in my scenario noone will ever have the desire to buy more than 1 piece of any item i'm selling and noone will ever want to buy more than 3 items at the same time.

Then my HTML entry form will be simple enough, because the user must be logged in when ordering (Thus i already know their userID - and it is held in my php $_SESSION['userID'] global variable), the order is always dynamically assigned at the time when user clicks CHECKOUT button (submits the form) and so the only thing we need the user to ENTER is the item ID (or rather pick it from a drop down list for example).

so here is VERY SIMPLE entry form:

<form action='orderit.php' method='post'>
    <select name='item[]'>
        <option value='' selected='selected'>Pick an item from the list!</option>
        <option value='1'>Knife</option>
        <option value='2'>Spoon</option>
        <option value='3'>Lava lamp</option>
        <option value='4'>HB pencil</option>
    </select><br/>
    <select name='item[]'>
        <option value='' selected='selected'>Pick an item from the list!</option>
        <option value='1'>Knife</option>
        <option value='2'>Spoon</option>
        <option value='3'>Lava lamp</option>
        <option value='4'>HB pencil</option>
    </select><br/>
    <select name='item[]'>
        <option value='' selected='selected'>Pick an item from the list!</option>
        <option value='1'>Knife</option>
        <option value='2'>Spoon</option>
        <option value='3'>Lava lamp</option>
        <option value='4'>HB pencil</option>
    </select><br/><br/>
    <input type='submit' value=' Checkout ' name='do'/>
</form>

From the above you see than when when user clicks checkout all the data (namely the choices the customer made are sent to the action which is set to orderit.php . Please note that i am not bothered about making sure the user is submiting valid information and i'm not using the latest technology (that being msqli) instead i'm using the deprecated mysql routines.

So here it follows:

<?php
     //here you will have your database opened, session initiated and so on
     // $db contains the database connection handler
     // $_POST['userID'] contains valid user's id

     if (isset($_POST['item']) && count($_POST['item'])>0) {
         //they ordered something we can create the order
         $q=mysql_query("INSERT INTO orders SET user='".mysql_real_escape_string($_SESSION['userID'])."'",$db);
         if (!$q)
             die("An error while creating new order");
         $orderID=mysql_insert_id($db); //fetch the just-now created order's ID
         foreach($_POST['item'] as $item) { //go through all the ordered items
            $q=mysql_query("INSERT INTO orderitems SET order='$orderID', item='".abs((int) $item)."'");
            if (!$q)
                die("Couldn't save item $item of order #$orderID");
         }
         print "Your order was saved successfuly!";
     } else
         die("This is an empty order");
?>

And that's all.

Please note that i am writing this code from top of my head now, so there may be typos or other types of error. take it more as an approximate guide rather than as a working piece of code.