mysql query not working - mysql

Question

i am working on a query which joins several tables.here's the code.
the query works fine until the time i add the third line SUM(SaleItems_T.qtymajor) AS sales. i get an error message which says
Unknown column 'SaleItems_T.qtymajor' in 'field list'
I am trying to build an reorder worksheet.Help is much appreciated.
SELECT ProductMaster_T.ProductName_VC AS PGroup,
StockMain_T.ItemDescription AS Item,
SUM(SaleItems_T.qtymajor) AS sales,
stockbuffers_T.buffer_qty AS BufferQty,
(stkbalance_T.AJ1+stkbalance_T.AR2+stkbalance_T.AD3+stkbalance_T.DX4) AS Stock,
(stkbalance_T.AJ1+stkbalance_T.AR2+stkbalance_T.AD3+stkbalance_T.DX4)-stockbuffers_T.buffer_qty AS Result
FROM ProductMaster_T, StockMain_T, stockbuffers_T, stkbalance_T
WHERE StockMain_T.ItemCode = stockbuffers_T.itemcode
AND
StockMain_T.ItemCode = stkbalance_T.itemid
AND
ProductMaster_T.ProductID = StockMain_T.ProdID
AND
SaleItems_T.ItemID = StockMain_T.ItemCode
ORDER BY
ProductName_VC,ItemDescription ASC

Answer 1

You haven't referenced the SaleItems_T table in your query, either in the FROM clause, or through a JOIN.

Answer 2

This is where your query is wrong:
FROM ProductMaster_T, StockMain_T, stockbuffers_T, stkbalance_T
Change that to:
FROM ProductMaster_T, StockMain_T, stockbuffers_T, stkbalance_T, SaleItems_T

Answer 3

(Please no vote for this. I only put it here as comment space is not suitable fot such long comment.)
You should really use explicit JOIN ... ON join_condition syntax instead of the implicit JOIN via WHERE conditions (this is really old way to do it). It's better because it's hard to forget a condition (or a table, as you did!) and thus less error-prone. It also separates the join conditions (which you'll use in almost every query) from the other conditions you may have in various queries.
So, instead of
FROM ProductMaster_T, StockMain_T
WHERE ProductMaster_T.ProductID = StockMain_T.ProdID
write:
FROM ProductMaster_T
JOIN StockMain_T
ON ProductMaster_T.ProductID = StockMain_T.ProdID
It's also nice to use aliases (with the (optional) AS keyword). It make code more readable:
FROM ProductMaster_T AS p
JOIN StockMain_T AS m
ON p.ProductID = m.ProdID
The whole query could be written as:
SELECT
master.ProductName_VC AS PGroup,
main.ItemDescription AS Item,
SUM(items.qtymajor) AS sales,
buf.buffer_qty AS BufferQty,
(bal.AJ1 + bal.AR2 + bal.AD3 + bal.DX4)
AS Stock,
(bal.AJ1 + bal.AR2 + bal.AD3 + bal.DX4) - buf.buffer_qty
AS Result
FROM ProductMaster_T AS master
JOIN StockMain_T AS main
ON master.ProductID = main.ProdID
JOIN stockbuffers_T AS buf
ON main.ItemCode = buf.itemcode
JOIN stkbalance_T AS bal
ON main.ItemCode = bal.itemid
JOIN SaleItems_T AS items
ON items.ItemID = main.ItemCode
ORDER BY
ProductName_VC ASC,
ItemDescription ASC
GROUP BY ??? main.ItemCode ??? --- depends on your tables'
--- relationships