How can I diagnose if a specific table within the 'mydata' file is causing the error 12002?

To diagnose if a specific table is causing the error, try running `REPAIR TABLE table_name;` for each table in the database. If the error only occurs when repairing a specific table, that table is likely the source of the corruption. Analyze the table structure and data for potential issues like large, corrupted indexes or data inconsistencies. Consider restoring a backup of just that table if available. You can also try exporting the table data to a text file and examining it for abnormalities.