want to display GLMethod query in sap b1

Please assistance to fetch the GLMethod :

I americium trying pursuing query to show the GLMethod arsenic Item Group, Item Level oregon Warehouse type. 

SELECT T0.[ItemCode], T0.[ItemName], T0.[GLMethod]
Case
When C Then 'Item Group'
When L Then 'Item Level'
When W Then 'Warehouse'
End As GLMethod

FROM OITM T0