如何为每次出现的特定值创建新行

Question

我需要一些指导来解决这个问题issue.I有一个类似于下面的数据集

Record_type         Record_Text
H01                 ABCDEFGHI123456789
D45                 BCDEFGH098765
D20                 BABRTHYUHU56789
D30                 QWERTY09876558471255
D12                 ASDFGHJ9814752
H02                 UGHRYCGDF12304025
G80                 YHNBGTRFV0147852
H01                 MLOPKIJUHNB624817
D20                 PLKIJUNHMY7653235
H15                 MVNBDGETDGSTEX9874
D30                 GNHGDTBFJVNV834687
H02                 JDGHKDGHSDFIG7845387
D60                 GHCNDBDGCTEF45367

H01 的每次出现都会启动一个新事务。基于以上示例，有两个事务（H01 到 G80 和 H01 到 D60）。

我需要根据每笔交易的某些条件 select 来自 RECORD_TEXT 字段的某些字符。我尝试使用以下代码单独进行第一笔交易

SELECT
 ( MAX(CASE WHEN RECORD_TYPE = 'H01' THEN (SUBSTR(RECORD_TEXT,1,10))  END)
|| MAX(CASE WHEN  RECORD_TYPE = 'D20' THEN ',' || (SUBSTR(RECORD_TEXT,2,3))     END)
|| MAX(CASE WHEN  RECORD_TYPE = 'D30' THEN ',' ||  (SUBSTR(RECORD_TEXT,9,8)) END)
|| MAX(CASE WHEN  RECORD_TYPE = 'H02' THEN ',' ||    (SUBSTR(RECORD_TEXT,13,4)) END)) AS TOTAL_FIELD
FROM   TABLE

我得到了预期的输出。

ABCDEFGHI1,ABR,87655847,0402

但我无法进行后续交易。

我对上述示例的预期输出（两个事务 = 两行）将是

ABCDEFGHI1,ABR,87655847,0402
MLOPKIJUHN,LKI,JVNV8346,G784

总共有大约200笔交易。我正在使用 Teradata 版本 14。请帮忙。

Answer 1

这是一个分析功能的工作，我对teradata不熟悉，但应该与其他地方提供的类似

查找分区依据，检查此 link

http://www.tutorialspoint.com/teradata/teradata_partitioned_primary_index.htm

你基本上可以按照你想要的方式切片你的数据所以你会做这样的事情

分区依据Record_type

除非您按照 Tyron78 的建议添加列，否则您还必须使用其他分析函数来创建算法来确定中间记录属于该集合。

希望对您有所帮助

Answer 2

DECLARE @t table(
  CREATE_TMSP int, Record_type nvarchar(20), Record_Text nvarchar(50)
);

INSERT INTO @t VALUES(1,'H01','ABCDEFGHI123456789');
INSERT INTO @t VALUES(2,'D45','BCDEFGH098765');
INSERT INTO @t VALUES(3,'D20','BABRTHYUHU56789');
INSERT INTO @t VALUES(4,'D30','QWERTY09876558471255');
INSERT INTO @t VALUES(5,'D12','ASDFGHJ9814752');
INSERT INTO @t VALUES(6,'H02','UGHRYCGDF12304025');
INSERT INTO @t VALUES(7,'G80','YHNBGTRFV0147852');
INSERT INTO @t VALUES(8,'H01','MLOPKIJUHNB624817');
INSERT INTO @t VALUES(9,'D20','PLKIJUNHMY7653235');
INSERT INTO @t VALUES(10,'H15','MVNBDGETDGSTEX9874');
INSERT INTO @t VALUES(11,'D30','GNHGDTBFJVNV834687');
INSERT INTO @t VALUES(12,'H02','JDGHKDGHSDFIG7845387');
INSERT INTO @t VALUES(13,'D60','GHCNDBDGCTEF45367');

WITH cte AS(
  SELECT RECORD_TYPE, RECORD_TEXT, DENSE_RANK() OVER(ORDER BY CREATE_TMSP) AS DERIVED_COLUMN
    FROM @t
),
cteLead AS(
  SELECT Record_Type, Record_Text, DERIVED_COLUMN AS DERIVED_COLUMN_LEFT, ISNULL(LEAD(DERIVED_COLUMN) OVER (ORDER BY DERIVED_COLUMN), 999999) AS DERIVED_COLUMN_RIGHT
   FROM cte
   WHERE Record_type = 'H01'
),
cteSplit AS(
SELECT a.DERIVED_COLUMN_LEFT AS ID, a.Record_Type AS RecordTypeHead, a.Record_Text AS RecordTextHead, a.DERIVED_COLUMN_LEFT, a.DERIVED_COLUMN_RIGHT,
       b.Record_Type,
       CASE
         WHEN b.Record_type = 'H01' THEN SUBSTRING(b.RECORD_TEXT,1,10)
         WHEN b.Record_type = 'D20' THEN SUBSTRING(b.RECORD_TEXT,2,3)
         WHEN b.Record_type = 'D30' THEN SUBSTRING(b.RECORD_TEXT,9,8)
         WHEN b.Record_type = 'H02' THEN SUBSTRING(b.RECORD_TEXT,13,4)
       END AS RecordTextSplit
 FROM cteLead AS a
 JOIN cte AS b ON b.DERIVED_COLUMN >= a.DERIVED_COLUMN_LEFT AND b.DERIVED_COLUMN < a.DERIVED_COLUMN_RIGHT
 WHERE b.Record_type IN ('H01', 'D20', 'D30', 'H02')
 )
 --
 SELECT * FROM cteSplit
 PIVOT
 (
    MAX(RecordTextSplit)
    FOR Record_Type IN (H01, D20, D30, H02)
 ) AS pvt

Answer 3

添加时间戳列后，可以轻松地为每笔交易分配唯一编号。然后您可以应用您现有的计算：

SELECT
   trans#,
      MAX(CASE WHEN RECORD_TYPE = 'H01' THEN        (SUBSTR(RECORD_TEXT, 1,10)) END)
   || MAX(CASE WHEN RECORD_TYPE = 'D20' THEN ',' || (SUBSTR(RECORD_TEXT, 2, 3)) END)
   || MAX(CASE WHEN RECORD_TYPE = 'D30' THEN ',' || (SUBSTR(RECORD_TEXT, 9, 8)) END)
   || MAX(CASE WHEN RECORD_TYPE = 'H02' THEN ',' || (SUBSTR(RECORD_TEXT,13, 4)) END)) AS TOTAL_FIELD
FROM 
 (
  SELECT CREATE_TMSP,RECORD_TYPE, RECORD_TEXT, 
     -- assign a unique number to each transaction
     SUM(CASE WHEN Record_type = 'H01' THEN 1 ELSE 0 END) 
     OVER (ORDER BY CREATE_TMSP
           ROWS UNBOUNDED PRECEDING) AS trans#
  FROM table
  -- more efficient to filter unneeded data before the OLAP function
  WHERE RECORD_TYPE IN ('H01','D20','D30','H02')
  -- uncomment if the data doesn't start with an 'H01' row and you don't want partial transactions
  -- QUALIFY trans# > 0
 ) AS dt
GROUP BY trans#

如何为每次出现的特定值创建新行

How to create new rows for every occurrence of a particular value

sql

teradata