如何聯接兩個具有相同屬性的表？

Question

我有兩個表，我想使用兩個表中的數據創建一個具有相同屬性的新表。 以下是我正在嘗試的代碼

/* Create a table called NAMES */
CREATE TABLE NAMES(Id integer PRIMARY KEY, Name varchar(100));
CREATE TABLE GAMES(Id integer PRIMARY KEY, Name varchar(100));
CREATE TABLE JJ(Id integer PRIMARY KEY, Name varchar(100));

/* Create few records in this table */
INSERT INTO NAMES VALUES(1,'Tom');
INSERT INTO NAMES VALUES(2,'Lucy');
INSERT INTO NAMES VALUES(3,'Frank');
INSERT INTO NAMES VALUES(4,'Jane');
INSERT INTO NAMES VALUES(5,'Robert');
INSERT INTO GAMES VALUES(7,'Football');
INSERT INTO GAMES VALUES(6,'Rugby');
COMMIT;

/* Display all the records from the table */
SELECT * FROM NAMES;
SELECT * FROM GAMES;
INSERT INTO JJ (Id, Name) VALUES((SELECT * FROM NAMES), (SELECT * FROM GAMES));

SELECT * FROM JJ; 'Error: near line 21: sub-select returns 2 columns - expected 1'

Answer 1

這將適用於oracle：

INSERT INTO JJ (Id, Name)((SELECT * FROM NAMES) union all(SELECT * FROM GAMES));

對於mysql：

   insert into JJ select * from Names union all select * from Games;

但是正如Zaynul所說，當兩個主鍵匹配時，它將引發錯誤！

Answer 2

您嘗試合並兩個表的方式不是更好b / c兩個不同的表主鍵可能相同，這將在插入第三個表（重復鍵）時引發錯誤。 我更喜歡更改您的表結構，使所有三個表的主鍵自動遞增並僅推送名稱而不是id

INSERT INTO JJ ( Name)
select name from (
SELECT name FROM NAMES
union all
SELECT name FROM GAMES
) t

Answer 3

我建議將JJ聲明為：

CREATE TABLE JJ (
    Id integer auto_increment PRIMARY KEY,
    Name varchar(100)
);

insert into jj (name)
    select name from names union all
    select game from games;