更新在Oracle

Question

在表中的列值從另一個表我需要更新表t1與來自表t2 NEW_ID列old_id列值，其中old_id被表t2匹配

T1

old_id name desc 
----------------------- 
1  a  abc 
2  b  def 
3  c  adf 
null d  ghi 

T2

new_id old_id code 
---------------------- 
x  1  ab 
y  2  cd 
z  3  gh 

我的輸出應該像

T1

old_id name desc 
----------------------- 
x  a  abc 
y  b  def 
z  c  adf 
null d  ghi 

Answer 1

嘗試使用

update t1 set t1.old_id=(select min(t2.new_id) from t2 where t2.old_id=t1.old_id) 

或

update t1 set t1.old_id=(select max(t2.new_id) from t2 where t2.old_id=t1.old_id) 

要查看將使用此查詢

select t1.*, (select max(t2.new_id) from t2 where t2.old_id=t1=old_id) as futureIdvalue from t1  

Answer 2

UPDATE 
T1 
SET 
T1.old_id= T2.new_id 
FROM 
T1, 
T2 
WHERE 
T1.old_id= T2.old_id; 

Answer 3

上做出的第變化e開頭幾個假設：

1. 我認爲沒有在T2表中的問題類型和第三紀錄old_id = 3
2. 因爲你有Desc列，什麼是Oracle我的保留字我將所有列視爲帶引號的標識符。

這是我的代碼（最後更新語句）。

CREATE TABLE T1 
    ("old_id" VARCHAR2(50), 
    "name" VARCHAR2(50), 
    "desc" VARCHAR2(50) 
); 
/
CREATE TABLE T2 
    (
    "new_id" VARCHAR2(50), 
    "old_id" VARCHAR2(50), 
    "code" VARCHAR2(50) 
); 
/

INSERT INTO T1 VALUES('1', 'a', 'abc'); 
INSERT INTO T1 VALUES('2', 'b', 'def'); 
INSERT INTO T1 VALUES('3', 'c', 'adf'); 
INSERT INTO T1 VALUES(NULL, 'd', 'ghi'); 

INSERT INTO T2 VALUES('x', '1', 'ab'); 
INSERT INTO T2 VALUES('y', '2', 'cd'); 
INSERT INTO T2 VALUES('z', '3', 'gh'); 

UPDATE t1 
    SET "old_id" = (SELECT "new_id" 
        FROM t2 
        WHERE t1."old_id" = t2."old_id");