MYSQL创建具有唯一值的表

Question

我想从另一个表更新我的表。我想忽略重复项，并删除该表中的所有匹配项。

Source Table   Table 1    Table 2 
Customer | Address Customer | Address Customer | Address 
__________________ __________________ __________________ 

Mike  123 Main Mike  123 Main  Bob  999 1st 
Steve  456 Maple Steve  456 Maple 
John  789 Elm  John  789 Elm 
Bob  999 1st 

例如，表2只“源表”进行比较，见表1。之后我使用MYSQL/PHP有独特的条目。

任何方向非常感谢。

Answer 1

SQL Fiddle

MySQL的32年5月5日架构设置：

CREATE TABLE Source 
    (`Customer` varchar(5), `Address` varchar(9)) 
; 

INSERT INTO Source 
    (`Customer`, `Address`) 
VALUES 
    ('Mike', '123 Main'), 
    ('Steve', '456 Maple'), 
    ('John', '789 Elm'), 
    ('Bob', '999 1st'), 
    ('Bob', '999 1st') 
; 

CREATE TABLE Table1 
    (`Customer` varchar(5), `Address` varchar(9)) 
; 

INSERT INTO Table1 
    (`Customer`, `Address`) 
VALUES 
    ('Mike', '123 Main'), 
    ('Steve', '456 Maple'), 
    ('John', '789 Elm') 
; 

CREATE TABLE Table2 
    (`Customer` varchar(5), `Address` varchar(9)) 
; 

DELETE FROM Table2; 
INSERT INTO Table2 
    (`Customer`, `Address`) 
SELECT DISTINCT Customer, Address 
FROM Source 
WHERE NOT EXISTS (SELECT 1 FROM Table1 WHERE Source.Customer = Table1.Customer) 

查询1：

SELECT * 
FROM Table2 

Results：

| CUSTOMER | ADDRESS | 
|----------|---------| 
|  Bob | 999 1st |