danep Posted August 28, 2006 Share Posted August 28, 2006 Hi everyone! Okay, here's my problem in a nutshell: I know how to combine tables "vertically" (using UNION), and "horizontally" (using JOIN)... but what if I need to do both? Let me explain.I have three tables: a shopping cart (containing, among other things, a product ID and session id), a product inventory (containing a product ID and product name/info), and a list of previously purchased items (containing the product ID and associated invoice number). What I need to do is basically create a data set of all items currently in the user's shopping cart, plus all items on one of their previous orders, and then order all of that by product name. I've tried using a join like so:"SELECT * FROM cart, invoice_details INNER JOIN inventory ON inventory.id=cart.id OR inventory.id=invoice_details.id WHERE cart.session='$user_session' OR invoice_details.invoice_id=$invoice_id ORDER BY product_name"Dunno if that makes sense... anyway, this query returns hundreds of results, basically everything from invoice_details and the user's cart - not at all what I was aiming for. So then I tried"(SELECT * FROM cart INNER JOIN inventory ON inventory.id=cart.id WHERE cart.session='$user_session') UNION ALL (SELECT * FROM invoice_details INNER JOIN inventory ON inventory.id=invoice_details.id WHERE invoice_details.invoice_id=$invoice_id) ORDER BY class"This throws and error, a la Warning: mysql_fetch_object(): supplied argument is not a valid MySQL result resource.Can anybody offer an alternative or point out what's wrong? Link to comment https://forums.phpfreaks.com/topic/18941-combining-tables-vertically-and-horizontally-phew/ Share on other sites More sharing options...
fenway Posted August 28, 2006 Share Posted August 28, 2006 The UNION should be fine, but the number/type of the columns has to match up, so that's for sure the problem. Link to comment https://forums.phpfreaks.com/topic/18941-combining-tables-vertically-and-horizontally-phew/#findComment-81892 Share on other sites More sharing options...
danep Posted August 28, 2006 Author Share Posted August 28, 2006 You're correct, the only column they have in common is "id". So instead of selecting all columns I tried "(SELECT inventory.name FROM cart......) UNION ALL (SELECT inventory.name FROM invoice.....)" , and it throws the same error. Now it seems to me, that since the column being returned in both selects is identical, that this should work. Do all columns have to match even if they're not being selected? Or is this just bad syntax on my part?Update: sorry, edited for clarity Link to comment https://forums.phpfreaks.com/topic/18941-combining-tables-vertically-and-horizontally-phew/#findComment-81897 Share on other sites More sharing options...
danep Posted August 28, 2006 Author Share Posted August 28, 2006 So, once again, this is the query I am using:[code]SELECT inventory.item_nameFROM cartINNER JOIN inventory ON inventory.item_id=cart.item_idWHERE cart.session='$user_session'UNION ALLSELECT inventory.item_nameFROM invoice_detailsINNER JOIN inventory ON inventory.item_id=invoice_details.item_id WHERE invoice_details.invoice_id=$invoice_id[/code]And I'm getting a syntax error. Each select by itself runs fine, it's something to do with the Union that's causing an error. Link to comment https://forums.phpfreaks.com/topic/18941-combining-tables-vertically-and-horizontally-phew/#findComment-81946 Share on other sites More sharing options...
fenway Posted August 29, 2006 Share Posted August 29, 2006 Strange... the same field, from the same table, just UNIONed, should be fine... Link to comment https://forums.phpfreaks.com/topic/18941-combining-tables-vertically-and-horizontally-phew/#findComment-81973 Share on other sites More sharing options...
danep Posted August 29, 2006 Author Share Posted August 29, 2006 I noticed my hosting company is running MySQL 3.23.58, which I gather is pretty behind the times. Could this be the problem? Sorry, probably should've mentioned this earlier but didn't notice until now. Link to comment https://forums.phpfreaks.com/topic/18941-combining-tables-vertically-and-horizontally-phew/#findComment-81999 Share on other sites More sharing options...
fenway Posted August 29, 2006 Share Posted August 29, 2006 Yup -- no UNION. Link to comment https://forums.phpfreaks.com/topic/18941-combining-tables-vertically-and-horizontally-phew/#findComment-82223 Share on other sites More sharing options...
danep Posted August 29, 2006 Author Share Posted August 29, 2006 Thanks! Wish I had thought of that sooner! Link to comment https://forums.phpfreaks.com/topic/18941-combining-tables-vertically-and-horizontally-phew/#findComment-82265 Share on other sites More sharing options...
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