Error
Error Code:
1110
MySQL Error 1110: Duplicate Column Specification
Description
MySQL Error 1110, 'Column '%s' specified twice', indicates that a SQL statement contains a column name listed more than once where uniqueness is required. This error typically occurs during data retrieval (SELECT), data manipulation (INSERT), or schema definition (CREATE TABLE, ALTER TABLE) when the same column name is inadvertently repeated.
Error Message
Column '%s' specified twice
Known Causes
4 known causesDuplicate SELECT Column
Occurs when the same column name appears multiple times in the `SELECT` clause of a query without distinct aliases, leading to an ambiguous or redundant selection.
Redundant INSERT Column
Happens when the target column list in an `INSERT` statement explicitly specifies the same column name more than once, violating the unique column expectation.
Duplicate CREATE TABLE Column
Arises when defining a new table and listing the same column name multiple times within the column definitions, resulting in an invalid table schema.
Redundant ALTER TABLE Column
Triggered when attempting to add a column using `ALTER TABLE ADD COLUMN` and the specified column name already exists or is repeated in the alteration statement.
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