@Override
    public Collection<SQLToken> generateSQLTokens(final SelectStatementContext sqlStatementContext) {
        Collection<SQLToken> result = new LinkedHashSet<>();
        ShardingSphereSchema schema = sqlStatementContext.getTablesContext().getSchemaName().map(schemas::get).orElseGet(() -> defaultSchema);
        for (OrderByItem each : getGroupByItems(sqlStatementContext)) {
            if (each.getSegment() instanceof ColumnOrderByItemSegment) {
                ColumnSegment columnSegment = ((ColumnOrderByItemSegment) each.getSegment()).getColumn();
                Map<String, String> columnTableNames = sqlStatementContext.getTablesContext().findTableNames(Collections.singleton(columnSegment), schema);
                generateSQLToken(columnSegment, columnTableNames).ifPresent(result::add);
            }
        }
        return result;
    }
@Test
    void assertGenerateSQLTokens() {
        assertThat(generator.generateSQLTokens(buildSelectStatementContext()).size(), is(1));
    }