Class 00 - Successful Completion
Class 01 - Warning
Class 02 - No Data (this is also a warning class per the SQL standard)
Class 03 - SQL Statement Not Yet Complete
Class 08 - Connection Exception
Class 09 - Triggered Action Exception
Class 0A - Feature Not Supported
Class 0B - Invalid Transaction Initiation
Class 0F - Locator Exception
Class 0L - Invalid Grantor
Class 0P - Invalid Role Specification
Class 0Z - Diagnostics Exception
Class 20 - Case Not Found
Class 21 - Cardinality Violation
Class 22 - Data Exception
Class 23 - Integrity Constraint Violation
Class 24 - Invalid Cursor State
Class 25 - Invalid Transaction State
Class 26 - Invalid SQL Statement Name
Class 27 - Triggered Data Change Violation
Class 28 - Invalid Authorization Specification
Class 2B - Dependent Privilege Descriptors Still Exist
Class 2D - Invalid Transaction Termination
Class 2F - SQL Routine Exception
Class 34 - Invalid Cursor Name
Class 38 - External Routine Exception
Class 39 - External Routine Invocation Exception
Class 3B - Savepoint Exception
Class 3D - Invalid Catalog Name
Class 3F - Invalid Schema Name
Class 40 - Transaction Rollback
Class 42 - Syntax Error or Access Rule Violation
Class 44 - WITH CHECK OPTION Violation
Class 53 - Insufficient Resources
Class 54 - Program Limit Exceeded
Class 55 - Object Not In Prerequisite State
Class 57 - Operator Intervention
Class 58 - System Error (errors external to PostgreSQL itself)
Class F0 - Configuration File Error
Class HV - Foreign Data Wrapper Error (SQL/MED)
Class P0 - PL/pgSQL Error
Class XX - Internal Error