Error
Error Code:
3107
MySQL Error 3107: Generated Column Definition Order
Description
This error occurs when you define a generated column in MySQL that attempts to reference another generated column which is defined later in the same `CREATE TABLE` or `ALTER TABLE` statement. MySQL enforces a strict dependency order, requiring any referenced generated column to be defined prior to the column that uses it in its expression. This ensures logical consistency and prevents undefined dependencies.
Error Message
Generated column can refer only to generated columns defined prior to it.
Known Causes
3 known causesIncorrect Generated Column Order
A generated column's expression references another generated column that is defined later in the `CREATE TABLE` or `ALTER TABLE` statement, violating MySQL's dependency rule.
Misplaced Column Definitions
The sequence of column definitions within the SQL statement does not align with the computational dependencies of the generated columns.
Attempted Circular Dependency
While not directly causing this error, an attempt to create a circular dependency between generated columns will inevitably lead to this error for one of the columns due to the strict ordering requirement.
Solutions
Coming SoonDetailed step-by-step solutions for this error are being prepared. In the meantime, try these general troubleshooting tips:
General Troubleshooting Tips
- Check the error message carefully for specific details
- Review recent changes that might have caused the error
- Search for the exact error code in the official documentation
- Check log files for additional context
- Try restarting the application or service