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Informix Error -26214: Cannot perform this operation on an external table.

Cause and resolution

Cannot perform this operation on an external table.

The following types of operations with external tables are not allowed: - including an external table in a subquery or in an outer join - including BLOB or CLOB columns from external tables in joins, UNION clauses, or ORDER BY clauses - including a subquery or stored procedure if the main query references BLOB or CLOB columns in external tables - using subscripts as BLOB or CLOB columns from external tables - selecting BLOB or CLOB columns from external tables out of order - selecting a BLOB or CLOB column from one external table and inserting it into a different external table - selecting BYTE and TEXT column to temporary table or through client API

Oninit® Troubleshooting Guidance

Reasons / Common Causes

-26214 fires when a statement uses an external table in one of several unsupported ways — per the official guidance.

  1. An external table included in a subquery or outer join, per the official guidance — the first named case.
  2. BLOB/CLOB columns from external tables used in joins, UNION clauses, or ORDER BY clauses, per the official guidance — the second named case.
  3. A subquery or stored procedure used when the main query references BLOB/CLOB columns in external tables, per the official guidance — the third named case.
  4. Subscripts used on BLOB/CLOB columns from external tables, per the official guidance — the fourth named case.
  5. BLOB/CLOB columns from external tables selected out of order, per the official guidance — the fifth named case.
  6. A BLOB/CLOB column selected from one external table and inserted into a different external table, per the official guidance — the sixth named case.
  7. BYTE/TEXT columns selected into a temporary table or through a client API, per the official guidance — the seventh named case.
Solutions / Resolution
  1. Restructure the statement to avoid the listed unsupported external-table usage, per the official guidance — e.g. avoid subqueries/outer joins on external tables, and select BLOB/CLOB/BYTE/TEXT columns from external tables directly and in order, without joins/unions/subscripts/reordering.
Examples
N/A

No specific triggering statement is documented beyond one of the listed restricted usages.

Diagnostic Checks
  1. Check the statement against the list of unsupported external-table operations, and restructure it to avoid the one triggered.
Related Errors / Related Topics
  • -26187 — "Cannot select from multiple external tables." A related external-table restriction, on referencing more than one external table rather than one of these specific unsupported operations.
  • -26198 — "Cannot modify an external table that is also used in the subquery." A related, more specific instance of the subquery restriction this error covers broadly.

The statement used an external table in an unsupported way (subquery/outer join, BLOB/CLOB joins/ordering, out-of-order selection, cross-table BLOB/CLOB insert, or BYTE/TEXT into a temp table/client API) — restructure it.