@Override
    public ComparableExpression<T> coalesce(Expression<T> expr) {
        Coalesce<T> coalesce = new Coalesce<T>(getType(), mixin);
        coalesce.add(expr);
        return coalesce.getValue();
    }
Create a {@code coalesce(this, expr)} expression

@param expr additional argument
@return coalesce
querydsl-core/src/main/java/com/querydsl/core/types/dsl/ComparableExpression.java