@Override
    public boolean equals(Object o) {
        if (o != null && getClass().equals(o.getClass())) {
            return ((GroupExpression<?,?>) o).getExpression().equals(expr);
        } else {
            return false;
        }
    }
Create an alias for the expression

@return alias expression
querydsl-core/src/main/java/com/querydsl/core/group/AbstractGroupExpression.java