In many places in the SQL syntax, you can represent the name of a column by qualifying it with a table-Name or correlation-Name.
In some situations, you cannot qualify a column-Name with a table-Name or a correlation-Name, but must use a Simple-column-Name instead. Those situations are:
SELECT c11 AS col1, c12 AS col2, c13 FROM t1 FOR UPDATE of c11,c13In this example, the correlation-Name col1 FOR c11 is not permitted because c11 is listed in the FOR UPDATE list of columns. You can use the correlation-Name FOR c12 because it is not in the FOR UPDATE list.
-- C.Country is a column-Name qualified with a -- correlation-Name. SELECT C.Country FROM APP.Countries C