從表中更新值如果從其他兩個表值匹配

Question

我想更新大約800行，並想更新table_c它從table_A和table_b匹配兩個值。 table_a和table_c通過value_id關聯。

例子：

CREATE TABLE TABLE_A (VALUE_ID INTEGER, PERSON_ID INTEGER, LAST_NAME VARCHAR2(15), FIRST_NAME VARCHAR2(15)); 
CREATE TABLE TABLE_B (VALUE_ID INTEGER, LAST_NAME VARCHAR2(15), FIRST_NAME VARCHAR2(15), ALIAS_ID INTEGER); 
CREATE TABLE TABLE_C (VALUE_ID INTEGER, ALIAS_ID INTEGER, PERSON_ID INTEGER); 
----- 
INSERT INTO TABLE_A (VALUE_ID, PERSON_ID, LAST_NAME, FIRST_NAME) 
VALUES (1, 6069, 'SMITH', 'JOHN'); 
INSERT INTO TABLE_A (VALUE_ID, PERSON_ID, LAST_NAME, FIRST_NAME) 
VALUES (2, 6111, 'ADAMS', 'JOHN'); 
INSERT INTO TABLE_A (VALUE_ID, PERSON_ID, LAST_NAME, FIRST_NAME) 
VALUES (3, 6117, 'ADAMS', 'SAM'); 
---- 
INSERT INTO TABLE_B (VALUE_ID, LAST_NAME, FIRST_NAME, ALIAS_ID) 
VALUES (4, 'SMITH', 'JOHN', 40856); 
INSERT INTO TABLE_B (VALUE_ID, LAST_NAME, FIRST_NAME, ALIAS_ID) 
VALUES (5, 'ADAMS', 'JOHN', 3425); 
INSERT INTO TABLE_B (VALUE_ID, LAST_NAME, FIRST_NAME, ALIAS_ID) 
VALUES (6, 'ADAMS', 'SAM', 40831); 
----- 
INSERT INTO TABLE_C (VALUE_ID, ALIAS_ID, PERSON_ID) 
VALUES (7, 28, 6069); 
INSERT INTO TABLE_C (VALUE_ID, ALIAS_ID, PERSON_ID) 
VALUES (8, 1022, 6111); 
INSERT INTO TABLE_C (VALUE_ID, ALIAS_ID, PERSON_ID) 
VALUES (9, 40473, 6117)

---

我一直在使用一個更新語句來完成這個和/或UPDATE語句嘗試，但它不工作。不知道我是否需要IF/ELSE語句。

最後，表B和表C中的alias_id必須相同。所以，這就是爲什麼table_C會被更新的原因。

這是我迄今爲止

UPDATE TABLE_C 
SET C.ALIAS_ID = (SELECT B.ALIAS_ID 
       FROM TABLE_B B 
       JOIN TABLE_A A 
       ON A.FIRST_NAME = B.FIRST_NAME AND A.LAST_NAME = B.LAST_NAME); 

Answer 1

您可以使用使用UPDATE ... FROM SQL Server語法以下查詢：

UPDATE TABLE_C 
SET ALIAS_ID = b.ALIAS_ID 
FROM TABLE_C AS c 
INNER JOIN TABLE_A AS a ON c.PERSON_ID = a.PERSON_ID 
INNER JOIN TABLE_B AS b ON a.FIRST_NAME = b.FIRST_NAME 
          AND a.LAST_NAME = b.LAST_NAME 

這可能在Oracle中爲你工作：

MERGE 
INTO TABLE_C 
USING (
    SELECT c.PERSON_ID AS pid, b.ALIAS_ID AS bAlias 
    FROM TABLE_C AS c 
    JOIN TABLE_A AS a ON c.PERSON_ID = a.PERSON_ID 
    JOIN TABLE_B AS b ON a.FIRST_NAME = b.FIRST_NAME 
         AND a.LAST_NAME = b.LAST_NAME  
) 
ON (PERSON_ID = pid) 
WHEN MATCHED THEN 
UPDATE 
SET ALIAS_ID = bAlias;