full join的一些问题--拼接所有的字段

    drop table if exists lqh_test1;
    drop table if exists lqh_test2;
    drop table if exists lqh_test3;
    drop table if exists lqh_test4;
    
    create table lqh_test1(id string,a string);
    create table lqh_test2(id string,b string);
    create table lqh_test3(id string,c string);
    create table lqh_test4(id string,d string);
    
    insert into lqh_test1 values('001','1');
    insert into lqh_test2 values('001','2');
    insert into lqh_test4 values('001','4');
    
    drop view if exists a;
    create view a as 
    select
    aa.id,
    a,