View Executes Too Slow

i have written a query and created it as a view

when i run the query it takes less that 5 seconds to give results

but when i run the view it takes about a minute

can anyone help please, it keeps giving me time out errors

here is the query.


SELECT
MAX(B.Code) AS Code,
MAX( T.Description) AS Type,
MAX( WH.Description) AS Warehouse,
MAX(B.Barcode) AS Barcode,
MAX(B.BatchNo) AS BatchNo,
MAX(B.CustomField) AS CustomField,
MAX(B.Colour) AS Colour,
MAX(Q.Quality) AS Quality,
MAX(round( M.ConvFactor, 2, 2)) AS ConvFactor,
MAX( M.Multiply) AS Multiply,
MAX(CONVERT(VARCHAR(20),
round((B.BoughtQty + B.TransferQty + B.IssuedQty + B.ReturnedQty + B.AdjustmentQty), 2)))
+ ' ' + MAX( M.UoM) AS Available,
CASE WHEN MAX( M.Multiply) = 'M'
THEN MAX(CONVERT(VARCHAR(20),
round(((B.BoughtQty + B.TransferQty + B.IssuedQty + B.ReturnedQty + B.AdjustmentQty) * M.ConvFactor), 2)))
+ ' ' + MAX(M.AUoM)
ELSE max(CONVERT(Varchar(50),convert(float,
round(((B.BoughtQty + B.TransferQty + B.IssuedQty + B.ReturnedQty + B.AdjustmentQty) / M.ConvFactor), 2))) )
+ ' ' + MAX( M.AUoM)
END AS AvailableAlternative,
MAX(BC.Supplier) AS Supplier,
MAX( OD.SupplierCode) AS SupplierCode
FROM cvrbatches B
LEFT JOIN SciposA.dbo.cvrmaster M ON M.Code = B.Code
LEFT JOIN cvrbatchctrl BC ON B.Code = BC.Code
AND B.Type = BC.Type
AND B.BatchNo = BC.BatchNo
INNER JOIN SciposA.dbo.cvrwhcontrol WH ON WH.Warehouse = B.Warehouse
INNER JOIN SciposA.dbo.cvrtypes T ON T.CoverType = B.Type
INNER JOIN cvrquality Q ON Q.Code = B.Quality AND B.Type = Q.Type
LEFT JOIN SciposA.dbo.cvrgrndetail GD ON GD.BatchNo = B.BatchNo AND B.Warehouse = GD.Warehouse
LEFT JOIN SciposA.dbo.cvrorderdetails OD ON OD.OrderNo = GD.OrderNo AND OD.LineN = GD.LineN
GROUP BY B.Barcode