protected boolean hasRow() {
        SQLQuery<?> query = new SQLQuery<Void>(connection(), configuration).from(entity);
        for (SQLListener listener : listeners.getListeners()) {
            query.addListener(listener);
        }
        query.addListener(SQLNoCloseListener.DEFAULT);
        addKeyConditions(query);
        return query.select(Expressions.ONE).fetchFirst() != null;
    }
Execute the clause and return the generated keys as a ResultSet

@return result set with generated keys
querydsl-sql/src/main/java/com/querydsl/sql/dml/SQLMergeClause.java