cannot_coerce Cannot Coerce — SQLSTATE 42846

A cast between the two types is not allowed.

• The error is written to the server log and returned to the client carrying SQLSTATE 42846.
• Any driver (libpq, JDBC, psycopg, npgsql, pgx) surfaces this code in its error object so you can branch on it programmatically.
• PL/pgSQL can trap it by name: EXCEPTION WHEN cannot_coerce THEN.

Severity: ERROR  |  PostgreSQL versions: 12, 13, 14, 15, 16, 17

Reproduce with the exact statement and read the full message in the server log (raise log_min_messages / set log_min_error_statement for more context).

No cast path exists between the source and target types.

Steps to resolve 42846:

1. Use a supported intermediate cast (for example via text) or a conversion function.
2. Confirm a cast exists for these types in the catalog.

Reference: PostgreSQL error codes — Class 42 (Syntax Error or Access Rule Violation).