hibernate/hibernate-orm · error · SemanticException

All query parts in a query group must have the same arity

Error message

All query parts in a query group must have the same arity

What it means

Error "All query parts in a query group must have the same arity" thrown in hibernate/hibernate-orm.

Source

Thrown at hibernate-core/src/main/java/org/hibernate/query/sqm/tree/spi/select/SqmQueryGroup.java:164

		final int firstSelectionSize = firstSelections.size();
		final List<SqmTypedNode<?>> typedNodes = new ArrayList<>( firstSelectionSize );
		for ( int i = 0; i < firstSelectionSize; i++ ) {
			typedNodes.add( firstSelections.get( i ).getSelectableNode() );
		}
		validateQueryGroupFetchStructure( typedNodes );
	}

	private void validateQueryGroupFetchStructure(List<? extends SqmTypedNode<?>> typedNodes) {
		final int firstSelectionSize = typedNodes.size();
		for ( int i = 0; i < queryParts.size(); i++ ) {
			final SqmQueryPart<T> queryPart = queryParts.get( i );
			if ( queryPart instanceof SqmQueryGroup<?> queryGroup ) {
				queryGroup.validateQueryGroupFetchStructure( typedNodes );
			}
			else if ( queryPart instanceof SqmQuerySpec<?> querySpec ) {
				final var selections = querySpec.getSelectClause().getSelections();
				if ( firstSelectionSize != selections.size() ) {
					throw new SemanticException( "All query parts in a query group must have the same arity" );
				}
				for ( int j = 0; j < firstSelectionSize; j++ ) {
					final SqmTypedNode<?> firstSqmSelection = typedNodes.get( j );
					final JavaType<?> firstJavaType = firstSqmSelection.getNodeJavaType();
					final JavaType<?> nodeJavaType = selections.get( j ).getNodeJavaType();
					if ( nodeJavaType != null && firstJavaType != null && firstJavaType != nodeJavaType ) {
						throw new SemanticException(
								"Select items of the same index must have the same java type across all query parts"
						);
					}
					if ( firstSqmSelection instanceof SqmFrom<?, ?> firstFrom ) {
						final var from = (SqmFrom<?, ?>) selections.get( j ).getSelectableNode();
						validateFetchesMatch( firstFrom, from );
					}
				}
			}
			else {
				throw new AssertionFailure( "Unrecognized SqmQueryPart subtype" );

View on GitHub (pinned to fad1729dce)

Solutions

1. Ensure every query part in the UNION/INTERSECT/EXCEPT group selects the same number of items.
2. Count the selections of each query part and align them (add/remove selections so arities match).
3. If one part intentionally selects fewer columns, pad it with null literals or dummy expressions of the right type.

When it happens

Trigger: Query parts combined with set operations (UNION/INTERSECT/EXCEPT) select a different number of items.

Common situations: A UNION of two criteria queries where one selects extra columns; align the select lists of all query parts.

AI-assisted analysis of hibernate/hibernate-orm@fad1729dce (2026-08-22). Data as JSON: /api/errors/3f7b0780787d176a. Report an issue: GitHub.