Get max row from multiple columns using VALUES clause

get max row from multiple columns in same row using VALUES clause.sql

/* This method has the best performance over other methods normally used (union all, etc)*/

SELECT TOP 50
	INV.PONUMBER
	,INV.KEYINDATE
	,INV.PAIDDATE
	,INV.DATE
	,
	(SELECT
			MAX(LASTUPDATEDATE)
		FROM (VALUES (INV.KEYINDATE), (INV.PAIDDATE), (INV.DATE)) AS UPDATEDATE (LASTUPDATEDATE))
	AS THIS_IS_THE_MAX_DATE_FROM_THE_3_COLUMNS
FROM OMC..INVOICES AS INV;

/*Other cool stuff you can do with the VALUES clause*/

SELECT
	*
FROM (VALUES ('Recommendation', 'Other'), ('Review', 'Marketing'), ('Internet', 'Promotion'))
AS SOURCE (NEWNAME, NEWREASONTYPE);

Taken from this article: https://www.mssqltips.com/sqlservertip/4067/find-max-value-from-multiple-columns-in-a-sql-server-table/