左连接环境

mysql> CREATE TABLE customers
    -> (
    -> c_id    int  NOT NULL AUTO_INCREMENT,
    -> c_name  char(50)  NOT NULL,
    -> c_address char(50) NULL,
    -> c_city  char(50)  NULL,
    -> c_zip   char(10)  NULL,
    -> c_contact char(50) NULL,
    -> c_email char(255) NULL,
    -> PRIMARY KEY(c_id)
    -> );

mysql> INSERT INTO customers(c_id, c_name, c_address, c_city, c_zip, c_contact, c_email) VALUES
    -> (10001, ‘RedHook‘, ‘200 Street‘, ‘Tianjin‘, ‘300000‘, ‘LiMing‘, ‘[email protected]‘),
    -> (10002, ‘Stars‘, ‘333 Fromage Lane‘, ‘Dalian‘, ‘116000‘, ‘Zhangbo‘, ‘[email protected]‘),
    -> (10003, ‘Netbhood‘, ‘1 Sunny Place‘, ‘Qingdao‘, ‘266000‘, ‘LuoCong‘, NULL),
    -> (10004, ‘JOTO‘, ‘829 Riverside Drive‘, ‘Haikou‘, ‘570000‘, ‘YangShan‘, ‘[email protected]‘);

mysql> CREATE TABLE orders
    -> (
    -> o_num    int  NOT NULL AUTO_INCREMENT,
    -> O_date   datetime  NOT NULL,
    -> c_id     int  NOT NULL,
    -> PRIMARY  KEY(o_num)
    -> );

mysql> INSERT INTO orders(o_num, o_date, c_id) VALUES
    -> (30001, ‘2008-09-01‘, 10001),
    -> (30002, ‘2008-09-12‘, 10003),
    -> (30003, ‘2008-09-30‘, 10004),
    -> (30004, ‘2008-10-03‘, 10005),
    -> (30005, ‘2008-10-08‘, 10001);