Error
Error Code:
1120
MySQL Error 1120: Cross Dependency in OUTER JOIN
Description
MySQL Error 1120 indicates a logical issue within an `OUTER JOIN` clause where the `ON` condition creates an unintended or invalid dependency between tables. This error often arises when the `ON` clause refers to a column from a table that is not yet 'available' in the join order or creates a circular reference that breaks the outer join's intended logic.
Error Message
Cross dependency found in OUTER JOIN; examine your ON conditions
Known Causes
3 known causesIncorrect ON Clause Referencing
The `ON` condition in an `OUTER JOIN` might reference a column from a table that is not directly involved in that specific join pair or from a table later in the join sequence, creating an invalid dependency.
Complex Chained OUTER JOINs
When chaining multiple `OUTER JOIN`s, especially with intricate `ON` conditions, it's easy to introduce an unintended cross-dependency where one join's condition implicitly relies on another in a circular or invalid way.
Misunderstanding OUTER JOIN Logic
Users sometimes apply `OUTER JOIN`s with `ON` conditions that are more suitable for `INNER JOIN`s or `WHERE` clauses, inadvertently creating conditions that negate the outer join's purpose or introduce dependencies.
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