cannot merge into view “…”

Symptoms

A statement failed with SQLSTATE 0A000 (feature_not_supported), reported at severity ERROR. This is a Feature Not Supported condition: PostgreSQL emits the message cannot merge into view "…".

• The client receives SQLSTATE 0A000 (feature not supported).
• The operation is rejected at ERROR level; the statement does not complete.
• The server adds a DETAIL line with specifics (see below).

What the server log shows

ERROR:  cannot merge into view "…"
DETAIL:  MERGE is not supported for views with INSTEAD OF triggers for some actions but not all.
HINT:  To enable merging into the view, either provide a full set of INSTEAD OF triggers or drop the existing INSTEAD OF triggers.

Why PostgreSQL raises this

Class 0A (Feature Not Supported) means the statement was syntactically valid but asked for an operation this server does not implement, or that is not allowed in the current context.

As described in PostgreSQL’s Appendix A PostgreSQL Error Codes, SQLSTATE 0A000 carries the condition name feature_not_supported in class Feature Not Supported. (Paraphrased — see the linked reference for the exact wording.)

Common causes

• Using a SQL feature or option not implemented by this PostgreSQL version.
• Attempting an operation disallowed in the current context (e.g. inside a transaction block).
• Combining clauses that PostgreSQL does not support together.

How to fix it

1. Rewrite the statement to avoid the unsupported feature.
2. Check the version notes — the feature may exist in a newer release.
3. Move the operation outside the disallowed context if applicable.

Version applicability

This message text is present in PostgreSQL 17, 18, 19. It was introduced around PostgreSQL 17; earlier releases do not emit this exact text.

Related & next steps

• SQLSTATE 0A000 — Feature Not Supported (full reference)
• PostgreSQL error code index

Reference: PostgreSQL Appendix A PostgreSQL Error Codes.