Postgresql 带有select distinct和多个子查询的Postgres表

我在Postgres 9.2中有一个包含38个变量的表格，我需要选择“最佳”结果。
我需要的是：
将var1和var2与之区分开来：
同一行的最小var3和最小var4
最大var5，如果有多个结果，则同一行的最小var3、var6到var12
按条件排序的var13（先3，后6秒0），以及同一行的var14-var18

v1 v2 v3 v4 v5 v6 v7 v8 v9 v10 v11 v12 v13 v14 v15 v16 v17 v18 ...
1  1  2  a  2  a  .  .  .  .   .   .   0   .   .   .   .   .
1  1  1  b  1  b  .  .  .  .   .   .   3   .   .   .   .   .
1  2  4  c  3  c  .  .  .  .   .   .   3   .   .   .   .   .
1  2  3  d  4  d  .  .  .  .   .   .   6   .   .   .   .   .
2  1  1  a  3  a  .  .  .  .   .   .   3   .   .   .   .   .
3  1  3  a  2  a  .  .  .  .   .   .   6   .   .   .   .   .
3  1  2  b  4  b  .  .  .  .   .   .   0   .   .   .   .   .
4  1  3  a  4  a  .  .  .  .   .   .   3   .   .   .   .   .
4  1  6  b  2  b  .  .  .  .   .   .   0   .   .   .   .   .
4  2  2  c  2  c  .  .  .  .   .   .   0   .   .   .   .   .
4  3  5  d  3  d  .  .  .  .   .   .   3   .   .   .   .   .
4  3  4  e  4  e  .  .  .  .   .   .   6   .   .   .   .   .
4  3  7  f  4  f  .  .  .  .   .   .   3   .   .   .   .   .
...

结果应该是：

v1 v2 v3 v4 v5 v6 v7 v8 v9 v10 v11 v12 v13 v14 v15 v16 v17 v18
1  1  1  b  2  a  .  .  .  .   .   .   3   .   .   .   .   .
1  2  3  d  4  d  .  .  .  .   .   .   3   .   .   .   .   .
2  1  1  a  3  a  .  .  .  .   .   .   3   .   .   .   .   .
3  1  2  b  4  b  .  .  .  .   .   .   6   .   .   .   .   .
4  1  3  a  4  a  .  .  .  .   .   .   3   .   .   .   .   .
4  2  2  c  2  c  .  .  .  .   .   .   0   .   .   .   .   .
4  3  4  e  4  e  .  .  .  .   .   .   3   .   .   .   .   .
...

下面是表格的图像，其中彩色字段显示应选择的内容： 希望这有意义。

编辑：

在另一篇文章中获得了一个指针，用于为表提供创建和插入

create table parent (
  v1 character varying,
  v2 character varying,
  v3 character varying,
  v4 character varying,
  v5 character varying,
  v6 character varying,
  v7 character varying,
  v8 character varying,
  v9 character varying,
  v10 character varying,
  v11 character varying,
  v12 character varying,
  v13 character varying,
  v14 character varying,
  v15 character varying,
  v16 character varying,
  v17 character varying,
  v18 character varying
);

insert into parent values('1','1','2','a','2','a','x1','x1','x1','x1','x1','x1','0','x1','x1','x1','x1','x1');
insert into parent values('1','1','1','b','1','b','x2','x2','x2','x2','x2','x2','3','x2','x2','x2','x2','x2');
insert into parent values('1','2','4','c','3','c','x3','x3','x3','x3','x3','x3','3','x3','x3','x3','x3','x3');
insert into parent values('1','2','3','d','4','d','x4','x4','x4','x4','x4','x4','6','x4','x4','x4','x4','x4');
insert into parent values('2','1','1','a','3','a','x1','x1','x1','x1','x1','x1','3','x1','x1','x1','x1','x1');
insert into parent values('3','1','3','a','2','a','x1','x1','x1','x1','x1','x1','6','x1','x1','x1','x1','x1');
insert into parent values('3','1','2','b','4','b','x2','x2','x2','x2','x2','x2','0','x2','x2','x2','x2','x2');
insert into parent values('4','1','3','a','4','a','x1','x1','x1','x1','x1','x1','3','x1','x1','x1','x1','x1');
insert into parent values('4','1','6','b','2','b','x2','x2','x2','x2','x2','x2','0','x2','x2','x2','x2','x2');
insert into parent values('4','2','2','c','2','c','x3','x3','x3','x3','x3','x3','0','x3','x3','x3','x3','x3');
insert into parent values('4','3','5','d','3','d','x4','x4','x4','x4','x4','x4','3','x4','x4','x4','x4','x4');
insert into parent values('4','3','4','e','4','e','x5','x5','x5','x5','x5','x5','6','x5','x5','x5','x5','x5');
insert into parent values('4','3','7','f','4','f','x6','x6','x6','x6','x6','x6','3','x6','x6','x6','x6','x6');

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你尝试了什么？我尝试了很多不同的方法，我认为这会使问题变得太复杂。我尝试过连接、联合、with、子查询、窗口函数等等。我可以解决不同的部分，但找到一个单一的解决方案被证明是不成功的。