Advantage Error Guide
Problem: A column name in an SQL statement was found in multiple tables and, thus, was not uniquely identifiable.
Solution: Use a table alias or table name with the column name to uniquely identify it. For example, "SELECT field FROM table1, table2" is not valid if "field" exists in both "table1" and "table2" because it is ambiguous. You must specifically identify which table to use. For example, "SELECT table1.field from table1, table2".