Extract values from the String filed in SQL server

Thanks for responding. I am getting this error "Invalid length parameter passed to the LEFT or SUBSTRING function" for below set of data: 

Sample data for string: Number of Sales: <Area="XBA" Number="">0</a><XX>END

In this case the OrderNumbers are NULL's and the value is given as 0 for values field.

CREATE TABLE #temp (
	ID int,
	Sales nvarchar (MAX)
);

INSERT INTO #temp VALUES 
(1,'Number of Sales: <Area="ABC" Number = "1012,1013,1014,1015">4</a><ZZ>END'),
(2,'Number of Sales: <Area="CBA" Number="1011,1012,1013,1014,1015,1016,1017,1018,1019,1020">10</a><YY>END'),
(3,'Number of Sales: <Area="XBA" Number="">0</a><XX>END');

SELECT ID, 
--PATINDEX('%[0-9][0-9][0-9][0-9]%', Sales),
CASE WHEN PATINDEX('%[0-9][0-9][0-9][0-9]%', Sales) > 0 THEN SUBSTRING(Sales, PATINDEX('%[0-9][0-9][0-9][0-9]%', Sales), PATINDEX('%">%', Sales) - PATINDEX('%[0-9][0-9][0-9][0-9]%', Sales)) ELSE NULL END AS [Order Number],
SUBSTRING(Sales, PATINDEX('%">%', Sales) + 2, PATINDEX('%</a>%', Sales) - PATINDEX('%">%', Sales) - 2) AS [Values]
FROM #temp;

DROP TABLE #temp;

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