Oracle SQL，用于比较同一列中的数值

Question

我有一个具有这种结构的视图，该结构是3个表的组合，我需要针对这些表比较每个数字列（OCT_14，NOV_14，ETC。）中的值。

TABLE    PERIOD  COUNTRY  CODE  POSITION  OCT_14  NOV_14  DEC_14
TABLE_1  Q1      UK       123   EMPL      .2      .2      .2
TABLE_2  Q1      Uk       123   EMPL      .2      .2      .2
TABLE_3  Q1      UK       123   EMPL      .3      .4      .4

在上一篇文章中为我提供了以下代码，但是我需要澄清的事情很少。

如何使用Oracle SQL比较同一列中多个列的数值

我在查询中需要其他字段（PERIOD，COUNTRY，CODE和POSITION），并且每个字段都会创建一个唯一的ID。 比较将在查询中发生，查询将返回比较行，其中每个表的（PERIOD，COUNTRY，CODE和POSITION）相同。 最终，比较行将这样返回。

TABLE    PERIOD  COUNTRY  CODE  POSITION  OCT_14  NOV_14  DEC_14
TABLE_1  Q1      UK       123   EMPL      .2      .2      .2
TABLE_2  Q1      Uk       123   EMPL      .2      .2      .2
TABLE_3  Q1      UK       123   EMPL      .3      .4      .4
COMPARE                                   ATTN     ATTN    ATTN

当我运行此查询时，使用此查询而不是ATTN为比较行获取空值。 我相信是因为缺少这种独特的元素。 谢谢你的尽心帮助。

这是上一篇文章中的代码：

Create Table V(TName VARCHAR(5), Oct_14 NUMBER(5,2), Nov_14 NUMBER(5,2), Dec_14 NUMBER(5,2));

Insert into V values('T1', 1.2, 1.2, 1.2);
Insert into V values('T2', 1.4, 1.5, 1.6);
Insert into V values('T3', 1.5, 1.5, 1.7);

SELECT TName, To_Char(Oct_14) Oct_14, To_Char(Nov_14) Nov_14, To_Char(Dec_14) Dec_14 from V
UNION
SELECT 'Compare', 
(select 'ATTN' from dual where EXISTS (select 1 from V where TName = 'T3' and OCT_14 > ALL(SELECT
 OCT_14 FROM V WHERE TName IN ('T1','T2')))) Oct_14_Res,
(select 'ATTN' from dual where EXISTS (select 1 from V where TName = 'T3' and Nov_14 > ALL(SELECT
 Nov_14 FROM V WHERE TName IN ('T1','T2')))) Nov_14_Res,
(select 'ATTN' from dual where EXISTS (select 1 from V where TName = 'T3' and Dec_14 > ALL(SELECT
Dec_14 FROM V WHERE TName IN ('T1','T2')))) Dec_14_Res
FROM dual;

Answer 1

这是SQL Fiddle演示： http ://www.sqlfiddle.com/#!4/1462f7 /3

select "TABLE", "PERIOD", "COUNTRY", "CODE", "POSITION", to_char(Oct_14) Oct_14 , To_Char(Nov_14) Nov_14, To_Char(Dec_14) Dec_14  from Table1
union 
select 'COMPARE', '','', NULL, '',
(select 'ATTN' from dual where EXISTS (select 1 from Table1 where "TABLE" = 'TABLE_3' and OCT_14 > ALL(SELECT OCT_14 FROM Table1 WHERE "TABLE" IN ('TABLE_1','TABLE_2')))) Oct_14_Res,
(select 'ATTN' from dual where EXISTS (select 1 from Table1 where "TABLE" = 'TABLE_3' and Nov_14 > ALL(SELECT Nov_14 FROM Table1 WHERE "TABLE" IN ('TABLE_1','TABLE_2')))) Nov_14_Res,
(select 'ATTN' from dual where EXISTS (select 1 from Table1 where "TABLE" = 'TABLE_3' and Dec_14 > ALL(SELECT Dec_14 FROM Table1 WHERE "TABLE" IN ('TABLE_1','TABLE_2')))) Dec_14_Res
FROM dual;