hibernate/hibernate-orm · error · QueryException

Can't emulate on error clause on MySQL

Error message

Can't emulate on error clause on MySQL

What it means

Error "Can't emulate on error clause on MySQL" thrown in hibernate/hibernate-orm.

Source

Thrown at hibernate-core/src/main/java/org/hibernate/dialect/function/json/MySQLJsonTableFunction.java:168

				case EMPTY_ARRAY -> sqlAppender.appendSql( " default '[]' on error" );
			}
		}

		if ( definition.emptyBehavior() != null ) {
			switch ( definition.emptyBehavior() ) {
				case ERROR -> sqlAppender.appendSql( " error on empty" );
				case NULL -> sqlAppender.appendSql( " null on empty" );
				case EMPTY_OBJECT -> sqlAppender.appendSql( " default '{}' on empty" );
				case EMPTY_ARRAY -> sqlAppender.appendSql( " default '[]' on empty" );
			}
		}
	}

	@Override
	protected void renderJsonExistsColumnDefinition(SqlAppender sqlAppender, JsonTableExistsColumnDefinition definition, int clauseLevel, SqlAstTranslator<?> walker) {
		// jsonb_path_exists errors by default
		if ( definition.errorBehavior() != null && definition.errorBehavior() != JsonExistsErrorBehavior.ERROR ) {
			throw new QueryException( "Can't emulate on error clause on MySQL" );
		}
		sqlAppender.appendSql( definition.name() );
		sqlAppender.appendSql( ' ' );
		sqlAppender.appendSql( DdlTypeHelper.getTypeName( definition.type(),
						walker.getSessionFactory().getTypeConfiguration() ) );

		sqlAppender.appendSql( " exists" );
		if ( definition.jsonPath() != null ) {
			sqlAppender.appendSql( " path " );
			sqlAppender.appendSingleQuoteEscapedString( definition.jsonPath() );
		}
		else {
			sqlAppender.appendSql( " path '$." );
			sqlAppender.appendSql( definition.name() );
			sqlAppender.appendSql( "'" );
		}
	}
}

View on GitHub (pinned to fad1729dce)

Solutions

1. Remove the ON ERROR clause for MySQL.

When it happens

Trigger: Triggered when the application calls a Hibernate dialect feature that the configured database dialect cannot provide: Can't emulate on error clause on MySQL.

Common situations: Common when running against a database whose dialect lacks this capability, when a mapping or HQL/Criteria query requests unsupported functionality, or when the wrong dialect is configured for the database in use. Error: Can't emulate on error clause on MySQL.

AI-assisted analysis of hibernate/hibernate-orm@fad1729dce (2026-08-22). Data as JSON: /api/errors/938e57fafc3772b6. Report an issue: GitHub.