Error
Error Code:
3694
MySQL Error 3694: Invalid Regex Back-Reference
Description
MySQL Error 3694 indicates that a regular expression pattern contains an invalid back-reference. This typically happens when the pattern attempts to refer to a capturing group that does not exist or whose index is out of bounds, preventing the query from executing.
Error Message
Invalid back-reference in regular expression.
Known Causes
3 known causesReferencing Non-Existent Group
The regular expression pattern attempts to use a back-reference (e.g., \1, \2) that points to a capturing group which was not defined or is not present in the pattern.
Back-Reference Index Out of Range
The numerical index used in the back-reference exceeds the total number of capturing groups defined earlier in the regular expression, making the reference invalid.
Typographical Error in Pattern
A simple typo in the back-reference number (e.g., \1 instead of \2) or an error in defining the capturing groups can lead to this error.
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