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There are several approaches to resolve ambiguous rows when combining multiple tables:

1. Use aliases: When columns in different tables have the same name, use aliases to differentiate them. For example, if both tables have a column named "name," rename one of them to "table1name" and the other to "table2name."

2. Use JOIN conditions: Specify specific conditions to join the tables together, using columns that are distinct in each table. For example, if one table has a column named "ID" and the other has a column named "employeeID," join on those distinct columns.

3. Use subqueries or temporary tables: Use subqueries or temporary tables to break down the tables into smaller chunks, resolving any conflicts before combining them.

4. Use UNION instead of UNION ALL: Use UNION instead of UNION ALL to eliminate duplicate rows. UNION will remove any rows that appear in both tables, which can help to resolve ambiguities.

5. Change the data type: If columns have the same name but different data types, changing one of the data types can resolve the ambiguity. For example, if one table has a column named "age" that is an integer and the other has a column also named "age" that is a string, convert the string column to an integer before combining the tables.