problem of the procedure migration from the SQLServer2000 to MySQL

[lm761104]

SQLServer2000:Item                 Color                Quantity                   
-------------------- -------------------- -------------------------- 
Table                Blue                 124                        
Table                Red                  223                        
Chair                Blue                 101                        
Chair                Red                  210                        
SELECT CASE WHEN (GROUPING(Item) = 1) THEN 'ALL'
            ELSE ISNULL(Item, 'UNKNOWN')
       END AS Item,
       CASE WHEN (GROUPING(Color) = 1) THEN 'ALL'
            ELSE ISNULL(Color, 'UNKNOWN')
       END AS Color,
       SUM(Quantity) AS QtySum
FROM Inventory
GROUP BY Item, Color WITH ROLLUP

Item                 Color                QtySum                     
-------------------- -------------------- -------------------------- 
Chair                Blue                 101.00                     
Chair                Red                  210.00                     
Chair                ALL                  311.00                     
Table                Blue                 124.00                     
Table                Red                  223.00                     
Table                ALL                  347.00                     
ALL                  ALL                  658.00     MySQL:SELECT Item,
       Color,
       SUM(Quantity) AS QtySum
FROM Inventory
GROUP BY Item, Color WITH ROLLUP
Item                 Color                QtySum                     
-------------------- -------------------- -------------------------- 
Chair                Blue                 101.00                     
Chair                Red                  210.00                     
Chair                NULL                 311.00                     
Table                Blue                 124.00                     
Table                Red                  223.00                     
Table                NULL                 347.00                     
NULL                 NULL                 658.00  How can I replace the Grouping()
function of SQLServer 2000 in MySQL5 ?