SQL Получите самую высокую дату от 3 табелей

SELECT MAX(MaxDate) FROM (SELECT MAX(TradeDate) AS MaxDate FROM Office.Transactions WHERE BrokerID = 1 AND TradeDate IS NOT NULLUNIONSELECT MAX(EntryDate) AS MaxDate FROM Office.IOI WHERE BrokerID = 1UNIONSELECT MAX(EntryDate) AS MaxDate FROM Office.TradeNotes WHERE BrokerID = 1) AS X
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