Informix Error -531: Duplicate column column-name exists in view.

Reasons / Common Causes

-531 fires when CREATE VIEW viewname (col1, col2, ...) explicitly lists output column names and the same name appears more than once in that list.

1. The same alias listed twice in the view's column-name list — the direct, only cause.
2. A view built over a join of tables that share a column name, where the explicit column list was meant to disambiguate them but repeated a name instead of assigning distinct aliases.
3. Generated view DDL built from a column list that wasn't deduplicated before being written into the CREATE VIEW statement.

Solutions / Resolution

1. Review the list of column names and ensure each appears only once, per the official guidance.
2. Assign distinct names to columns that would otherwise collide, particularly when the view selects same-named columns from two joined tables.

Examples

The disallowed duplicate

CREATE VIEW order_summary (order_id, status, status) AS
  SELECT o.order_id, o.status, h.status FROM orders o, order_history h
  WHERE o.order_id = h.order_id;
-- -531: 'status' listed twice

Corrected with distinct names

CREATE VIEW order_summary (order_id, current_status, history_status) AS
  SELECT o.order_id, o.status, h.status FROM orders o, order_history h
  WHERE o.order_id = h.order_id;

Diagnostic Checks

1. Scan the CREATE VIEW column-name list for repeated entries before running the statement, especially when the view selects from a join of tables with overlapping column names.

Related Errors / Related Topics

No closely related error codes are cross-referenced for -531 in this set yet.

A duplicated name in the view's explicit column list — give the colliding columns distinct aliases.