Oracle视图创建

Question

我有一个像下面的图片

。

在输入表中，下名称列的每个值应该有五个步骤A，B，C，d，E ....但名“VINOD”具有3个值A，B，C和它们的相应的日期28.12.2013,11.10.2013和NULL。所以，在视图中，我应该为每个名称设置五个diffrenet列，如下所示。因为“Vinod”没有D和E，所以相应的日期应该是NA（但由于C值在表中是NULL，所以它只能被看作是NULL）。

希望我解释了我的查询。请帮助我。

在此先感谢。

Answer 1

你可以尝试：

SELECT name, 
     (CASE WHEN A_DATE IS NULL THEN 'NA' ELSE A_DATE END) as A_DATE, 
     (CASE WHEN B_DATE IS NULL THEN 'NA' ELSE B_DATE END) as B_DATE, 
     (CASE WHEN C_DATE IS NULL THEN 'NA' ELSE C_DATE END) as C_DATE, 
     (CASE WHEN D_DATE IS NULL THEN 'NA' ELSE D_DATE END) as D_DATE, 
     (CASE WHEN E_DATE IS NULL THEN 'NA' ELSE E_DATE END) as E_DATE 
    FROM (
     SELECT name, 
       (SELECT date 
        FROM inputtable as i2 
       WHERE i2.name=i1.name 
        AND i2.step = 'A') as A_DATE, 
       (SELECT date 
        FROM inputtable as i3 
       WHERE i3.name=i1.name 
        AND i3.step = 'B') as B_DATE, 
       (SELECT date 
        FROM inputtable as i4 
       WHERE i4.name=i1.name 
        AND i4.step = 'C') as C_DATE, 
       (SELECT date 
        FROM inputtable as i5 
       WHERE i5.name=i1.name 
        AND i5.step = 'D') as D_DATE, 
       (SELECT date 
        FROM inputtable as i6 
       WHERE i6.name=i1.name 
        AND i6.step = 'E') as E_DATE 
     FROM inputtable as i1 
     GROUP BY name 
     ) s1 

Answer 2

你不应该混合数据类型那样。 使用下面的测试案例：

-- drop table input_table; 

create table input_table(
    name  varchar2(20) not null 
    ,step  varchar2(10) not null 
    ,step_date varchar2(10) 
); 

insert into input_table(name, step, step_date) values('VINOD', 'A', '28.12.013'); 
insert into input_table(name, step, step_date) values('VINOD', 'B', '11.10.2013'); 
insert into input_table(name, step, step_date) values('VINOD', 'C', null); 

commit; 

以下（可怕的）查询应该做你要求什么：

select name 
    -- If a row exists (has flag) pick whatever value was there, otherwise set NA 
     ,case when max(a_flag) = 'A' then max(a_date) else 'NA' end as a_date 
     ,case when max(b_flag) = 'B' then max(b_date) else 'NA' end as b_date 
     ,case when max(c_flag) = 'C' then max(c_date) else 'NA' end as c_date 
     ,case when max(d_flag) = 'D' then max(d_date) else 'NA' end as d_date 
     ,case when max(e_flag) = 'E' then max(e_date) else 'NA' end as e_date 
    from (select name 
      -- Pivot the dates to columns 
       ,case when step = 'A' then step_date end as a_date 
       ,case when step = 'B' then step_date end as b_date 
       ,case when step = 'C' then step_date end as c_date 
       ,case when step = 'D' then step_date end as d_date 
       ,case when step = 'E' then step_date end as e_date 
      -- Create flags because we have two kinds of NULL... 
       ,case when step = 'A' then 'A' end as a_flag 
       ,case when step = 'B' then 'B' end as b_flag 
       ,case when step = 'C' then 'C' end as c_flag 
       ,case when step = 'D' then 'D' end as d_flag 
       ,case when step = 'E' then 'E' end as e_flag 
      from input_table 
     ) 
group 
    by name;