獲取每個組oracle的最大值

Question

我想根據以下記錄中的ID_DATE列獲取每個組中的最高值。 按ID_TOPIC

CREATE TABLE DA_TBL(
    DATA_ID  VARCHAR2(50),
    REF_DESC VARCHAR2(50),
    DATE_L DATE NOT NULL,
    ID_TOPIC  VARCHAR2(50),
    ID_DATE NUMBER
);

INSERT all 
INTO DA_TBL  VALUES  ('1','sample 1',CURRENT_TIMESTAMP, 'local', 1)
INTO DA_TBL  VALUES  ('2','sample 2',CURRENT_TIMESTAMP, 'tradition', 2)
INTO DA_TBL  VALUES  ('3','sample 2',CURRENT_TIMESTAMP, 'gospel', 3)
INTO DA_TBL  VALUES  ('4','sample 4',CURRENT_TIMESTAMP, 'local', 4)
INTO DA_TBL  VALUES  ('5','sample 5',CURRENT_TIMESTAMP, 'gospel', 5)
INTO DA_TBL  VALUES  ('6','sample 6',CURRENT_TIMESTAMP, 'tradition', 6)
INTO DA_TBL  VALUES  ('7','sample 7',CURRENT_TIMESTAMP, 'gospel', 7)
INTO DA_TBL  VALUES  ('8','sample 8',CURRENT_TIMESTAMP, 'local', 8)
INTO DA_TBL  VALUES  ('9','sample 9',CURRENT_TIMESTAMP, 'tradition', 9)
INTO DA_TBL  VALUES  ('10','sample 10',CURRENT_TIMESTAMP, 'local', 10)
INTO DA_TBL  VALUES  ('11','sample 11',CURRENT_TIMESTAMP, 'gospel', 11)
SELECT * FROM dual;

我想要的是：

DATA_ID|REF_DESC |ID_TOPIC |ROWNUMBER|
-------|---------|---------|---------|
9      |sample 9 |tradition|        1|
10     |sample 10|local    |        1|
11     |sample 11|gospel   |        1|

我得到的是：

DATA_ID|REF_DESC|ID_TOPIC |ROWNUMBER|
-------|--------|---------|---------|
9      |sample 9|tradition|        1|
8      |sample 8|local    |        1|
7      |sample 7|gospel   |        1|

我試過的

 SELECT *
  FROM (SELECT DATA_ID, REF_DESC, ID_TOPIC 
              , ROW_NUMBER() OVER (PARTITION BY ID_TOPIC ORDER BY DATA_ID DESC) AS rownumber
         FROM  DA_TBL ORDER BY DATA_ID DESC)
 WHERE rownumber = 1;

Answer 1

您的問題是DATA_ID列的數據類型。 它是一個字符串，字符串的排序方式與數字不同。 9 比 10“大”。

如果可以，請將列的數據類型修改為NUMBER 。

或者，在此處申請TO_NUMBER ：

ROW_NUMBER() OVER (PARTITION BY ID_TOPIC ORDER BY TO_NUMBER(DATA_ID) DESC)
                                                  ------------------
                                                  here

如果列包含字母數字值，這可能不起作用。

SQL> l
  1  SELECT *
  2    FROM (SELECT DATA_ID, REF_DESC, ID_TOPIC
  3                , ROW_NUMBER() OVER (PARTITION BY ID_TOPIC ORDER BY to_number(DATA_ID) DESC) AS rownumber
  4           FROM  DA_TBL ORDER BY DATA_ID DESC)
  5*  WHERE rownumber = 1
SQL> /

DATA_ID REF_DESC   ID_TOPIC    ROWNUMBER
------- ---------- ---------- ----------
9       sample 9   tradition           1
11      sample 11  gospel              1
10      sample 10  local               1

SQL>

Answer 2

嘗試以下查詢：

SELECT 
  t1.DATA_ID,
  t1.REF_DESC,
  t1.ID_TOPIC
FROM yourTable t1
JOIN (
  SELECT 
    ID_TOPIC, 
    MAX(ID_DATE) AS maxIdDate
  FROM yourTable 
  GROUP BY ID_TOPIC
) t2 ON t1.ID_TOPIC = t2.ID_TOPIC AND t1.ID_DATE = t2.maxIdDate

我認為您在查詢中使用了錯誤的列，因此如果您以這種方式修復它，它也應該有效：

SELECT 
  *
FROM (
  SELECT 
    DATA_ID, 
    REF_DESC, 
    ID_TOPIC,
    ROW_NUMBER() OVER (PARTITION BY ID_TOPIC ORDER BY ID_DATE DESC) AS rownumber
  FROM DA_TBL
) t
WHERE rownumber = 1;

Answer 3

這是因為您在DATA_ID上有varchar數據類型。

為了正確排序（您期望整數排序，而不是文本順序），您需要轉換它：

ROW_NUMBER() OVER (PARTITION BY ID_TOPIC ORDER BY CAST(DATA_ID AS NUMBER) DESC)

旁注：表中的數據類型是錯誤的——如果你有一個 ID，它自然應該存儲為一個數字（除非你有一些特殊要求）。

根據您發布的內容，您將兩個 ID 列存儲為varchar ，它應該是number 。

Answer 4

我想根據 ID_DATE 獲取每個組中的最高值

如果是這樣，你為什么關注DATA_ID ？

你想要的查詢是：

SELECT *
FROM (SELECT DATA_ID, REF_DESC, ID_TOPIC ,
             ROW_NUMBER() OVER (PARTITION BY ID_TOPIC ORDER BY ID_DATE DESC) AS rownumber
      FROM  DA_TBL
     )
WHERE rownumber = 1
ORDER BY TO_NUMBER(DATA_ID) DESC;

這是一個 db<>fiddle。