修复重复列 SQL

Question

我有以下代码：

update table
set 
offer_id_02 = offer_id_03,
offer_id_03 = offer_id_04,
offer_id_04 = offer_id_05,
offer_id_05 = offer_id_06,
offer_id_06 = offer_id_07,
offer_id_07 = offer_id_08,
offer_id_08 = NULL
where offer_id_02 = offer_id_01;


update table
set 
offer_id_03 = offer_id_04,
offer_id_04 = offer_id_05,
offer_id_05 = offer_id_06,
offer_id_06 = offer_id_07,
offer_id_07 = offer_id_08,
offer_id_08 = NULL
where offer_id_03 = offer_id_01 or offer_id_03 = offer_id_02; 


update table
set 
offer_id_04 = offer_id_05,
offer_id_05 = offer_id_06,
offer_id_06 = offer_id_07,
offer_id_07 = offer_id_08,
offer_id_08 = NULL
where offer_id_04 = offer_id_01 or offer_id_04 = offer_id_02 or offer_id_04 = offer_id_03;


update table
set 
offer_id_05 = offer_id_06,
offer_id_06 = offer_id_07,
offer_id_07 = offer_id_08,
offer_id_08 = NULL
where offer_id_05 = offer_id_01 or offer_id_05 = offer_id_02 or offer_id_05 = offer_id_03 or offer_id_05 = offer_id_04;


update table
set 
offer_id_06 = offer_id_07,
offer_id_07 = offer_id_08,
offer_id_08 = NULL
where offer_id_06 = offer_id_01 or offer_id_06 = offer_id_02 or offer_id_06 = offer_id_03 or offer_id_06 = offer_id_04 or offer_id_06 = offer_id_05;


update table
set 
offer_id_07 = offer_id_08,
offer_id_08 = NULL
where offer_id_07 = offer_id_01 or offer_id_07 = offer_id_02 or offer_id_07 = offer_id_03 or offer_id_07 = offer_id_04 or offer_id_07 = offer_id_05  or offer_id_07 = offer_id_06;


update table
set 
offer_id_08 = NULL
where offer_id_08 = offer_id_01 or offer_id_08 = offer_id_02 or offer_id_08 = offer_id_03 or offer_id_08 = offer_id_04 or offer_id_08 = offer_id_05 or offer_id_08 = offer_id_06 or offer_id_08 = offer_id_07;

本质上，我有一个包含客户的 SQL 表以及他们作为促销获得的 8 个优惠。由于逻辑错误，出现了一些重复的情况。为了解决这个问题，我“跳过”了重复的优惠并清空了 Offer_id_08 插槽。问题是，逻辑是不同的，具体取决于哪些报价彼此重复。我怎样才能以简洁的方式构建这个？

Answer 1

也许，作为第一步，您可以尝试使用 CASE 和组合 WHERE 将查询合并为一个大查询：

UPDATE table
SET offer_id_02 = 
   CASE 
      WHEN offer_id_02 = offer_id_01 THEN offer_id_03
      ELSE offer_id_02
   END,
   offer_id_03 = 
   CASE 
      WHEN offer_id_03 = offer_id_01 OR offer_id_03 = offer_id_02 THEN offer_id_04
      ELSE offer_id_03
   END,
  ...
  offer_id_08 = NULL
WHERE 
     offer_id_01 IN (offer_id_02, offer_id_03, offer_id_04, offer_id_05, offer_id_06, offer_id_07, offer_id_08)
  OR offer_id_02 IN (offer_id_03, offer_id_04, offer_id_05, offer_id_06, offer_id_07, offer_id_08)
  ...
  OR offer_id_07 = offer_id_08;

Answer 2

这是重新格式化（取消透视、展平）表格的简单方法，如 @JNevill 建议的那样，每个记录有 4 个重复属性用于说明。

create table the_table (
 id serial, 
 attr_1 integer, 
 attr_2 integer,
 attr_3 integer,
 attr_4 integer
);

insert into the_table (attr_1,attr_2,attr_3,attr_4) 
values 
 (10, 11, 12, 13),
 (20, 21, 22, 23),
 (30, 31, 32, 33);

select t.id, l.*
from the_table t
cross join lateral (
 select 'attr_1', attr_1 union all
 select 'attr_2', attr_2 union all
 select 'attr_3', attr_3 union all
 select 'attr_4', attr_4
) as l(attr_name, attr_value);

数据库小提琴