查询以合并 Oracle/Teradata 中的后续行

Question

我有一个table，数据如下

DB  DBMS INST   SCHEMA  TABLE   COLUMN  HDFT    N_Identity  Class
IDS TD   SBD    IDS   Data_Val  cust_t                      HIGH
IDS TD   SBD    IDS   Data_Val  cust_t  GID     
IDS TD   SBD    IDS   Data_Val  cust_t  Phone       
IDS TD   SBD    IDS   Data_Val  cust_t  Account     
IDS TD   SBD    IDS   Data_Val  cust_t  Visa        
IDS TD   SBD    IDS   Data_Val  cust_t  Mail        
IDS TD   SBD    IDS   Data_Val  cust_t  Email       
IDS TD   SBD    IDS   Data_Val  cust_t  Login   Yes 
TDS TD   FDT    TDS   Expense   Exp_t   Name                 LOW
TDS TD   FDT    TDS   Expense   Exp_t           Yes

我想要如下输出：

DB  DBMS INST   SCHEMA  TABLE   COLUMN  HDFT    N_Identity  Class
IDS TD   SBD    IDS   Data_Val  cust_t  GID     Yes         HIGH
IDS TD   SBD    IDS   Data_Val  cust_t  Phone   Yes         HIGH
IDS TD   SBD    IDS   Data_Val  cust_t  Account Yes         HIGH
IDS TD   SBD    IDS   Data_Val  cust_t  Visa    Yes         HIGH
IDS TD   SBD    IDS   Data_Val  cust_t  Mail    Yes         HIGH
IDS TD   SBD    IDS   Data_Val  cust_t  Email   Yes         HIGH
IDS TD   SBD    IDS   Data_Val  cust_t  Login   Yes         HIGH
TDS TD   FDT    TDS   Expense   Exp_t   Name    Yes         LOW

N_identity 对于特定的 column.So 将具有 Yes 或 No 值到目前为止我已经尝试使用以下查询但它没有给我想要的结果：

SELECT * FROM
(
   SELECT * FROM
   (
        SELECT DB,DBMS,INST,SCHEMA,TABLE,COLUMN, MAX(HDFT) as HDFT, MAX(N_Identity) as N_Identity, MAX(Class) as Class  
        FROM Table
        GROUP BY DB,DBMS,INST,SCHEMA,TABLE,COLUMN
   )a 

  UNION

  SELECT DB,DBMS,INST,SCHEMA,TABLE,COLUMN, HDFT, N_Identity, Class FROM Table

)b

WHERE HDFT IS NOT NULL
AND N_Identity IS NOT NULL
AND Class IS NOT NULL

更新要求： HDFT 值可以为空，以下是一种情况：

DB  DBMS INST   SCHEMA  TABLE   COLUMN  HDFT    N_Identity  Class
IDS TD   SBD    IDS   Data_Val  cust_t          No          INT
IDS TD   SBD    IDS   Data_Val  cust_t                      INT
IDS TD   SBD    IDS   Data_Val  cust_t          No

预期结果：

DB  DBMS INST   SCHEMA  TABLE   COLUMN  HDFT    N_Identity  Class
IDS TD   SBD    IDS   Data_Val  cust_t          No          INT

Answer 1

select db,dbms,inst,schema,table,column,hdft,
case when N_identity>0 then N_Identity else 'Yes' end as N_identity
,case when class>0 then class 
when column='cust_t' then 'HIGH'
when column='Exp_t' then 'LOW' end as Class
from table
where hdft>0

Answer 2

我想你需要 nvl() 和 first_value() 分析函数只是考虑在最后一步过滤 hdft is not null（在这些函数完成子查询操作之后）：

with tab2 as
(    
select db, dbms, inst, schema, "table", "column", hdft,
       first_value(class) over (partition by db) as class, 
       nvl(N_Identity,'Yes') as N_Identity 
  from tab                    
)
select * from tab2 where hdft is not null;

Demo

P.S。避免使用保留关键字来命名 table 或 table、column 等列。

Answer 3

您可以像这样使用 first_value 函数：

with selection as
(    
select db, dbms, inst, scheme, table1, column1, hdft,
       first_value(Class1) over (partition by db order by Class1) as "class1", 
       first_value(N_Identity) over (partition by db order by N_Identity)  as "N_Identity"
  from Y                 
)
select * from selection where hdft is not null;

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