or can you provide some sample (masked or fake) data, so at least we can visualise the issue and provide a suggestion for you.
>> SORRY, I can't share any piece of the data I'm working on so that you can help me
As Ryan suggested: Make it up. You can make up a test case similar to what you want with any data you can imagine.
Something like this:
SELECT mt.Item_Number, mt.Item_Manufacturing_Date, mt.Item_Sales_Date,
wt.Item_Warehousing_Date /*, ...*/
FROM dbo.main_table mt
OUTER APPLY (
SELECT TOP (1) wt.*
FROM dbo.warehouse_table wt
WHERE wt.Item_Number = mt.Item_Number
ORDER BY wt.Item_Warehousing_Date DESC
) AS wt
how's your SQL currently looks like?