MySQL error 1060, ER_DUP_FIELDNAME, occurs when a CREATE TABLE, ALTER TABLE, or SELECT ... INTO statement repeats a column name, causing a duplicate-column conflict.
MySQL Error 1060: ER_DUP_FIELDNAME signals that a statement tries to define the same column twice. Remove or rename the duplicate column, then rerun the DDL to resolve the issue.
Duplicate column name '%s'
MySQL throws error code 1060 with the condition name ER_DUP_FIELDNAME when a statement defines the same column name more than once. The server cannot create or modify a table when duplicate column identifiers appear in the column list.
The error frequently appears in CREATE TABLE, ALTER TABLE ADD COLUMN, and SELECT ... INTO statements.
It stops execution before any structural change is committed, protecting the catalog from ambiguity.
Duplicate column definitions in the same CREATE TABLE clause trigger the error immediately. MySQL checks each column identifier in sequence and raises 1060 once a repeat is found.
When ALTER TABLE adds a column that already exists, the runtime validator reports ER_DUP_FIELDNAME. Case sensitivity depends on lower_case_table_names settings; identical names differing only by case may still collide.
Derived tables or SELECT ...
INTO new_table statements inherit column aliases. Reusing an alias twice inside the SELECT list also produces the duplicate field name error.
Identify the repeated column and either drop, rename, or qualify it uniquely. In DDL, edit the offending column definition. In SELECT lists, assign distinct aliases with the AS keyword.
After adjusting the statement, rerun it.
MySQL will proceed once all column names are unique within the target table or result set.
During schema migrations, developers may copy column blocks and forget to alter the name. Reviewing migration scripts with code review tools prevents the issue.
ORM frameworks sometimes generate ALTER TABLE commands that add a column twice due to mis-configured models.
Sync the model state and regenerate the migration to remove duplicates.
Adopt descriptive, consistent naming conventions and lint SQL files to catch repeats early.
Use version control pull requests to surface accidental duplicates before deployment.
Galaxy’s SQL editor highlights duplicate identifiers in real time, and its AI copilot suggests unique aliases, reducing the chance of hitting 1060 in production.
Error 1061 ER_DUP_KEYNAME occurs when an index name duplicates another in the same table. Resolve by renaming or dropping the duplicate index.
Error 1050 ER_TABLE_EXISTS_ERROR indicates an attempt to create a table that already exists.
Use CREATE TABLE IF NOT EXISTS or choose a different name.
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Developers often copy column definitions and forget to change the name, resulting in two identical columns.
Migrations that add the same column in different steps collide when run together.
SELECT AVG(value) AS score, MAX(value) AS score repeats the alias score, provoking 1060 in SELECT ...
INTO.
On case-insensitive filesystems, Name and name are treated the same, triggering the error even if casing differs.
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Error 1060 exists in all supported MySQL versions. Behavior is consistent, though case-sensitivity rules may vary with lower_case_table_names.
On Unix systems with lower_case_table_names=0, Name and name are distinct. On Windows, they collide and raise 1060.
Galaxy’s editor underlines duplicate identifiers and its AI copilot proposes unique column names, reducing manual mistakes.
Yes. Because the statement fails before changes are applied, simply correct the SQL and rerun it; no rollback needed.
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