Adding two records together.

[someguy]

I am developing a shopping cart and have come across a problem. I have developed it in such a way that there is two carts, I call them the user_cart and the session_cart,, but they all really go to the same place and are only differentiated by the user_id or the cfid columns (one OR the other). I have developed them this way in case one use may have more than one account without cross-breeding information. When the user logs in, any items in his or her cart are added into their user cart. So you see, it is possible to have product # 5 (we'll say) twice.

I would use the GROUP BY command, but if the user deletes that item he or she would have to delete it more than once.

What I need is a way to look at the items the user has in his or her cart, look at the items in the session_cart and if there are any duplicates to add the quantity together.

To see the current status of my cart look at SomeGuysStuff.com

Thank you.

[Motoma]

I am developing a shopping cart and have come across a problem. I have developed it in such a way that there is two carts, I call them the user_cart and the session_cart,, but they all really go to the same place and are only differentiated by the user_id or the cfid columns (one OR the other). I have developed them this way in case one use may have more than one account without cross-breeding information. When the user logs in, any items in his or her cart are added into their user cart. So you see, it is possible to have product # 5 (we'll say) twice.

I would use the GROUP BY command, but if the user deletes that item he or she would have to delete it more than once.

What I need is a way to look at the items the user has in his or her cart, look at the items in the session_cart and if there are any duplicates to add the quantity together.

To see the current status of my cart look at SomeGuysStuff.com

Thank you.

I am not sitting in front of a MySQL database right now, however, depending on the version of MySQL you are using, you might be able to this with a subquery utilizing a union.

SELECT
    combined.item_id,
    sum(1)
FROM
    (SELECT * FROM cartTable WHERE id = 5
     UNION
     SELECT * FROM cartTable WHERE id = 7) combined
GROUP BY
    combined.item_id
 

[someguy]

That won't work the way I want it to. I need to actually make a change to the db not just display like data together.
Also I need to know how to find the rows that need changing.

[Motoma]

That won't work the way I want it to. I need to actually make a change to the db not just display like data together.
Also I need to know how to find the rows that need changing.

I know this doesn't really help that much, but you can use LIMIT with UPDATE and DELETE.

Could you try explaining your problem a little differently for me, I'm not sure I am grasping the whole thing.