hibernate/hibernate-orm · error · IllegalArgumentException

"Unsupported aggregate SQL type: " + aggregateColumn.getType

Error message

"Unsupported aggregate SQL type: " + aggregateColumn.getTypeCode()

What it means

Error ""Unsupported aggregate SQL type: " + aggregateColumn.getTypeCode()" thrown in hibernate/hibernate-orm.

Source

Thrown at hibernate-core/src/main/java/org/hibernate/dialect/aggregate/DB2AggregateSupport.java:363

			case JSON_ARRAY:
				if ( jsonSupport ) {
					return null;
				}
				break;
			case SQLXML:
			case XML_ARRAY:
				return null;
			case STRUCT:
				final var sb = new StringBuilder();
				appendStructCustomWriteExpression(
						aggregateColumn,
						aggregatedColumns,
						sb,
						aggregateColumn.getComponent().getMetadata().getTypeConfiguration()
				);
				return sb.toString();
		}
		throw new IllegalArgumentException( "Unsupported aggregate SQL type: " + aggregateColumn.getTypeCode() );
	}

	private static void appendStructCustomWriteExpression(
			ColumnTypeInformation aggregateColumnType,
			List<Column> aggregatedColumns,
			StringBuilder sb,
			TypeConfiguration typeConfiguration) {
		sb.append( aggregateColumnType.getTypeName() ).append( "()" );
		for ( Column udtColumn : aggregatedColumns ) {
			sb.append( ".." ).append( udtColumn.getName() ).append( '(' );
			if ( udtColumn.getSqlTypeCode() == STRUCT ) {
				final AggregateColumn aggregateColumn = (AggregateColumn) udtColumn;
				appendStructCustomWriteExpression(
						aggregateColumn,
						aggregateColumn.getComponent().getAggregatedColumns(),
						sb,
						typeConfiguration
				);

View on GitHub (pinned to fad1729dce)

Solutions

1. Map the aggregate column with a supported SQL type.
2. Avoid the unsupported aggregate type on DB2.

When it happens

Trigger: Triggered when the application calls a Hibernate dialect feature that the configured database dialect cannot provide: Unsupported aggregate SQL type (DB2).

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: Unsupported aggregate SQL type (DB2).

AI-assisted analysis of hibernate/hibernate-orm@fad1729dce (2026-08-22). Data as JSON: /api/errors/5c8b3baec3a68455. Report an issue: GitHub.