My query doesn't get the right value - sql

Question

My query doesn't give the right output.
I tried with different way such as with CTE as well but nothing help.
I'm trying to write View to display available products with quantity but as some data is not available in StockCloseInventory table it displaying me 0 even though records are available for some products.
Here is my query:
SELECT TOP (100) PERCENT
SOI.InStockPrdID
, SOI.ProdName
, SOI.TradeDrugId
, ISNULL(SOI.Quantity, 0) AS INQTY
, ISNULL(SCI.QuantitySold, 0) AS OUTQTY
, ISNULL(SOI.Quantity, 0) - ISNULL(SCI.QuantitySold, 0) AS AQTY
, SOI.UnitPrice
FROM dbo.StockInventory AS SOI
LEFT OUTER JOIN dbo.StockCloseInventory AS SCI
ON SOI.InStockPrdID = SCI.InStockPrdID
AND SOI.SoldOut <> 1
LEFT OUTER JOIN dbo.vwTradeDrug AS VTD
ON SOI.TradeDrugId = VTD.TradeDrugId
ORDER BY SOI.ProdName
And this is the output of my View:
And here is my Tables
Table: StockInventory
Table: StockCloseInventory
vwTradeDrug view:
CREATE VIEW [dbo].[vwTradeDrug]
AS
SELECT
T.TradeDrugId
, T.GenericDrugId
, T.TradeName
, G.GenericProprietaryName
, G.DosageType
, G.Strength
, T.TradeName + ',' + G.GenericProprietaryName + ',' + G.DosageType
+ ',' + G.Strength AS TradeFullName
FROM dbo.TradeDrug AS T
INNER JOIN Inventory.GenericDrug AS G
ON T.GenericDrugId = G.GenericId
GO

Answer 1

The problem is with SOI.SoldOut <> 1
First, as Pouya Kamyar pointed out, it is more conventional to include this in a WHERE clause than in a JOIN.
However, the issue is that the value of this field is mostly NULL.
What you want is something more like this:
WHERE SOI.SoldOut IS NULL
OR SOI.SoldOut <> 1

Answer 2

I Suggest bring "AND SOI.SoldOut <> 1" in WHERE clause not in join terms

Answer 3

Either change the null data in sold out to be 0 or 1 OR...
handle the nulls so that the boolean compare results in a true or false instead of "NULL" as below.
SELECT TOP (100) PERCENT
SOI.InStockPrdID
, SOI.ProdName
, SOI.TradeDrugId
, ISNULL(SOI.Quantity, 0) AS INQTY
, ISNULL(SCI.QuantitySold, 0) AS OUTQTY
, ISNULL(SOI.Quantity, 0) - ISNULL(SCI.QuantitySold, 0) AS AQTY
, SOI.UnitPrice
FROM dbo.StockInventory AS SOI
LEFT OUTER JOIN dbo.StockCloseInventory AS SCI
ON SOI.InStockPrdID = SCI.InStockPrdID
AND ISNULL(SOI.SoldOut,0) <> 1 -- this should do the trick
LEFT OUTER JOIN dbo.vwTradeDrug AS VTD
ON SOI.TradeDrugId = VTD.TradeDrugId
ORDER BY SOI.ProdName
Remember Boolean compares on Null values result in NULL (a third value in a Boolean compare!) so SOI.SoldOut <> 1 when SOI.SoldOut is null will result in NULL instead of a true/false you're expecting.