- column_name: The name of the column that is specified ambiguously.
- table_name_1: The first table being joined that contains a reference to the ambiguously defined column name.
- table_name_2: The second table being joined that contains a reference to the ambiguously defined column name.
Cause
A column name used in a join was defined in more than one table and was referenced ambiguously. In a join, any column name that occurs in more than one of the tables must be prefixed by its table name or table alias when referenced.
Action
To avoid ambiguity, prefix references to column names that exist in multiple tables with either the table name or a table alias and a period. For example, if tables EMP and DEPT are being joined and both contain the column DEPTNO, then all references to DEPTNO should be prefixed with the table name, as in EMP.DEPTNO or DEPT.DEPTNO.