hibernate/hibernate-orm · error · UnsupportedOperationException

Full join emulation does not support ignore case ordering fo

Error message

Full join emulation does not support ignore case ordering for union queries

What it means

Error "Full join emulation does not support ignore case ordering for union queries" thrown in hibernate/hibernate-orm.

Source

Thrown at hibernate-core/src/main/java/org/hibernate/sql/ast/spi/FullJoinEmulation.java:536

		final int count = tuple == null ? 1 : tuple.getExpressions().size();
		String separator = NO_SEPARATOR;
		for ( int i = 0; i < count; i++ ) {
			translator.appendSql( separator );
			renderFullJoinEmulationSortExpression(
					sortSpecification,
					sortSelectionIndexes[i],
					nullPrecedenceSelectionIndexes == null ? -1 : nullPrecedenceSelectionIndexes[i]
			);
			separator = COMMA_SEPARATOR;
		}
	}

	private void renderFullJoinEmulationSortExpression(
			SortSpecification sortSpecification,
			int sortSelectionIndex,
			int nullPrecedenceSelectionIndex) {
		if ( sortSpecification.isIgnoreCase() ) {
			throw new UnsupportedOperationException( "Full join emulation does not support ignore case ordering for union queries" );
		}
		if ( sortSelectionIndex < 0 ) {
			throw new UnsupportedOperationException( "Full join emulation requires order by expressions to be in the select list for union queries" );
		}

		final var sortOrder = sortSpecification.getSortOrder();
		final var nullPrecedence = resolveRenderedNullPrecedence( sortSpecification );
		final boolean renderNullPrecedence = nullPrecedence != null;
		final boolean supportsNullPrecedence = renderNullPrecedence && translator.getDialect().supportsNullPrecedence();
		if ( renderNullPrecedence && !supportsNullPrecedence ) {
			if ( nullPrecedenceSelectionIndex < 0 ) {
				throw new IllegalStateException( "Full join emulation null precedence index is missing for union query ordering" );
			}
			translator.appendSql( nullPrecedenceSelectionIndex + 1 );
			translator.appendSql( COMMA_SEPARATOR );
		}

		translator.appendSql( sortSelectionIndex + 1 );

View on GitHub (pinned to fad1729dce)

Solutions

1. Remove ignore-case ordering (lower-cased sort) from the union query using full join emulation.
2. Apply case-insensitive ordering by selecting the lowered expression explicitly and ordering by its position/alias.
3. Use a dialect that supports FULL JOIN natively so the emulation restrictions do not apply.

When it happens

Trigger: Full join emulation for a union query is combined with case-insensitive (ignore case) ordering.

Common situations: Using SortOrder with ignoreCase on a UNION query needing full join emulation; remove ignore case ordering.

AI-assisted analysis of hibernate/hibernate-orm@fad1729dce (2026-08-22). Data as JSON: /api/errors/4072e57ad9d09ae1. Report an issue: GitHub.