How to include another table in JOIN - mysql

Question

Below is my mysql query
SELECT
opensalesorder.so_number,
items.VendorName,
opensalesorder.item_number,
items_custom_fields.FieldValue AS `Stock Item`,
vendor_custom_fields.FieldValue AS `Paid Freight Allowance`,
items.QuantityOnHand,
items.ReorderPoint,
items.MaxQty,
SUM(opensalesorder.quantity_on_order),
items.PurchaseCost,
items.VendorName,
items.VendorName,
items.PurchaseCost,
opensalesorder.status,
items.ItemType
FROM
vendor,
`opensalesorder`
inner join items
on opensalesorder.item_number = items.ItemName
JOIN items_custom_fields
ON items_custom_fields.ItemName = items.ItemName
JOIN vendor_custom_fields
ON vendor_custom_fields.VName = vendor.VName
WHERE opensalesorder.item_number = items.ItemName
and items_custom_fields.FieldName ='Stock Item'
and vendor_custom_fields.FieldName ='Paid Freight Allowance'
and opensalesorder.status NOT LIKE 'on po'
AND opensalesorder.so_number NOT IN ('2','3')
AND items.VendorName NOT IN ('Access')
AND opensalesorder.item_number NOT IN ('018-0001')
group by opensalesorder.item_number
LIMIT 100
on executing this query I am getting error like
#1054 - Unknown column 'vendor.VName' in 'on clause'
But I have included the vendor table in FROM clause.
Is this right way to include a table in JOIN ?
So whats wrong is with this query ?
EDIT:
SHOW CREATE TABLE FOR opensalesorder
CREATE TABLE `opensalesorder` (
`so_number` decimal(10,0) NOT NULL,
`item_number` varchar(20) NOT NULL,
`quantity_on_order` int(11) NOT NULL,
`quantity_to_order` int(11) NOT NULL,
`status` varchar(20) NOT NULL,
`editsequence` text NOT NULL,
`TxnLineID` text NOT NULL,
`TxnID` text NOT NULL,
`dateCreated` date NOT NULL,
`shipDate` date NOT NULL,
`customer` text NOT NULL,
`itemclass` text NOT NULL,
UNIQUE KEY `unique_mapping` (`so_number`,`item_number`),
KEY `so_number` (`so_number`),
KEY `item_number` (`item_number`),
KEY `status` (`status`)
)
SHOW CREATE TABLE FOR items
CREATE TABLE `items` (
`ItemName` varchar(30) NOT NULL,
`VendorName` varchar(40) DEFAULT NULL,
`QuantityOnHand` int(11) DEFAULT NULL,
`QuantityOnSalesOrder` int(11) DEFAULT NULL,
`ReorderPoint` int(11) DEFAULT NULL,
`PurchaseCost` double DEFAULT NULL,
`AverageCost` double DEFAULT NULL,
`SalesPrice` double DEFAULT NULL,
`PurchaseDesc` varchar(200) DEFAULT NULL,
`SalesDesc` varchar(200) DEFAULT NULL,
`ItemType` varchar(30) DEFAULT NULL,
`FreeCode` int(11) DEFAULT NULL,
`SubGroup` varchar(10) DEFAULT NULL,
`DateNewItem` date DEFAULT NULL,
`Notes` text,
`MaxQty` int(11) DEFAULT NULL,
`QuantityOnPO` int(11) DEFAULT NULL,
PRIMARY KEY (`ItemName`),
KEY `ItemName` (`ItemName`),
KEY `VendorName` (`VendorName`)
)
SHOW CREATE TABLE FOR vendor_custom_fields
CREATE TABLE `vendor_custom_fields` (
`VName` text NOT NULL,
`FieldName` text NOT NULL,
`FieldValue` text NOT NULL,
`FieldType` text NOT NULL,
PRIMARY KEY (`VName`(120),`FieldName`(120)),
FULLTEXT KEY `VName_index` (`VName`)
)
SHOW CREATE TABLE FOR vendor
CREATE TABLE `vendor` (
`VName` varchar(60) NOT NULL,
`CompanyName` varchar(100) NOT NULL,
`Address1` varchar(120) NOT NULL,
`Address2` varchar(120) NOT NULL,
`City` varchar(40) NOT NULL,
`State` varchar(50) NOT NULL,
`PostalCode` varchar(13) NOT NULL,
`Phone` varchar(13) NOT NULL,
`Fax` varchar(13) NOT NULL,
`AlternatePhone` varchar(13) NOT NULL,
`AlternateContact` varchar(30) NOT NULL,
`Email` varchar(40) NOT NULL,
`AccountNumber` varchar(30) NOT NULL,
`Balance` double NOT NULL,
`RepEmail` varchar(40) NOT NULL,
`FreightAllowance` double DEFAULT NULL,
`MinimumPOLimit` double DEFAULT NULL,
`Notes` text NOT NULL,
PRIMARY KEY (`VName`)
)

Answer 1

I think the problem is mixing the implied join with the (unimplied) 'stated' joins. When I put 'vendor' in as a regular join the query was fine.
(I had to comment out references to 'items_custom_fields' as you didn't include the table definition)
Here's a fiddle.