JDBC ResultSet Columns with Table Aliases
When executing a query like "SELECT * from table1 a, table2 b where (WHATEVER)", accessing data with "resultSet.getString("a.columnName")" or "resultSet.getString("b.columnName")" fails.
The JDBC API does not explicitly address this scenario, leaving it vendor-dependent. However, you can resolve this issue by:
Option 1: Column Renaming
Name columns differently in the query using aliases, such as:
SELECT a.columnName as columnNameA, b.columnName as columnNameB, ... from table1 a, table2 b where (WHATEVER)
Then reference these aliases in your Java code:
resultSet.getString("columnNameA"); resultSet.getString("columnNameB");
Option 2: Column Position
Refer to columns by position in the result set:
resultSet.getString(1); resultSet.getString(2);
Note that JDBC uses one-based indexing, starting from 1 for the first column.
For safety and maintainability, Option 1 (Column Renaming) is recommended. If a query's column order changes, your code will break silently when accessing the wrong columns. By contrast, changing column names will raise a "no such column" exception, alerting you to the issue.
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