When encountering the error "1112: Column has invalid default value" in MySQL, perform the following actions:
- Identify the Affected Column and Table: Use the error message to identify which column and table are causing the issue. If the error message does not specify, you may need to look at recent changes to the database schema.
- Check the Default Value of the Column: Execute the following SQL query to inspect the default value of the problematic column. Replace `yourtablename` and `yourcolumnname` with the actual table and column names:
SHOW COLUMNS FROM yourtablename LIKE 'yourcolumnname';
- Validate the Default Value Against Column Type: Compare the default value obtained in the previous step with the column's data type. Ensure that the default value conforms to the data type's requirements (e.g., a numeric column should not have a text default value).
- Correct the Default Value: Depending on your findings, you might need to update the default value to match the column's data type. Use the following SQL command, replacing placeholders with actual values:
ALTER TABLE yourtablename MODIFY COLUMN yourcolumnname yourdatatype DEFAULT 'newvaliddefault_value';
Ensure that `'newvaliddefaultvalue'` is compatible with `yourdata_type`.
- Check for NULL Constraints: If the column is not allowed to be NULL (`NOT NULL` constraint), ensure the default value is not NULL unless the column is an auto-increment integer.
- Review Recent Schema Changes: If the issue started after recent changes, review those changes for any that might have affected the default value or data type of the column.
- Test the Changes: After applying the correction, test to ensure the error does not occur again. You might need to insert a new row (without specifying a value for the affected column) to verify that the default value is applied correctly.
- Revert Unintended Changes: If any unintended changes were made during the debugging process, make sure to revert them to maintain the integrity of your database schema.
By following these steps, you should be able to resolve the "1112: Column has invalid default value" error in MySQL.
