Question

列出与客户编号282具有相同代表编号的客户编号，客户名称和销售代表。这将需要是子查询，不要显式测试销售代表35。

 use premier_products;

SELECT customer.customer_num, customer.customer_name, rep.first_name 
FROM rep 
JOIN customer ON rep.rep_num = customer.rep_num 
WHERE customer_num = 282;

我对如何使用以下问题形成子查询感到困惑。 rep.rep_num = customer.rep_num.i知道如何将其形成为reguar方式，但需要了解如何在子查询中形成它。

这两个表之间只有两个相关的文件。

AND REP.FIRST_NAME REFERS TO SALES REP ...

架构＆＃39;

CREATE DATABASE premier_products;

代表

CREATE TABLE rep
(
rep_num char(2) primary key,

last_name varchar(15),

first_name varchar(15),

street varchar(15),

city varchar(15),

state char(2),

zip char(5),

commission decimal(7,2),

rate decimal(3,2) 

);

客户表

CREATE TABLE customer

(

customer_num char(3) primary key, 

customer_name varchar(30),

street varchar(15),

city varchar(15),

state char(15),

zip char(5),

balance decimal(7,2),

credit_limit decimal(7,2),

rep_num char(2)

);

订单表

CREATE TABLE orders

(

order_num char(5) primary key,

order_date timestamp,

customer_num char(3)

);

Order_line表

CREATE TABLE order_line

(

order_num char(5),

part_num char(4),

num_ordered int(5),

quoted_price decimal(7,2),

PRIMARY KEY (order_num, part_num)

);

部分表格

CREATE TABLE part

(

part_num char(4) primary key,

description varchar(20),

on_hand int(4),

class char(2),

warehouse char(2),

price decimal (7,2)
);

填充代表

INSERT INTO rep values ('20', 'Kaiser', 'Valerie', '624 Randall', 'Grove', 'FL', '33321', 20542.50, 0.05);

INSERT INTO rep values ('35', 'Hull', 'Richard', '532 Jackson', 'Sheldon', 'FL', '33553', 39216.00, 0.07);

INSERT INTO rep values ('65', 'Perez', 'Juan', '1626 Taylor', 'Fillmore', 'FL', '33336', 23487.00, 0.05);

填充客户表

INSERT INTO customer values ('148', 'Al''s Appliance and Sport', '2837 Greenway', 'Fillmore', 'FL', '33336',
6550.00, 7500.00, '20');

INSERT INTO customer values ('282', 'Brookings Direct', '3827 Devon', 'Grove', 'FL', '33321', 431.50, 10000.00, '35');

INSERT INTO customer values ('356', 'Ferguson''s', '382 Wildwood', 'Northfield', 'FL', '33146', 5785.00, 7500.00,
'65');

INSERT INTO customer values ('408', 'The Everything Shop', '1828 Raven', 'Crystal', 'FL', '33503', 5285.25, 5000.00, '35');

INSERT INTO customer values ('462', 'Bargains Galore', '3829 Central', 'Grove', 'FL', '33321', 3412.00, 10000.00, '65');

INSERT INTO customer values ('524', 'Kline''s', '838 Ridgeland', 'Fillmore', 'FL', '33336', 12762.00, 15000.00, '20');

INSERT INTO customer values ('608', 'Johnson''s Department Store', '372 Oxford', 'Sheldon', 'FL', '33553', 2106.00, 10000.00, '65');

INSERT INTO customer values ('687', 'Lee''s Sport and Appliance', '282 Evergreen', 'Altonville', 'FL', '32543', 2851.00, 5000.00, '35');

INSERT INTO customer values ('725', 'Deerfield''s Four Seasons', '282 Columbia', 'Sheldon', 'FL', '33553', 248.00, 7500.00, '35');

INSERT INTO customer values ('842', 'All Season', '28 Lakeview', 'Grove', 'FL', '33321', 8221.00, 7500.00, '20');

填充订单表

INSERT INTO orders value ('21608', '2015-10-20', '148');

INSERT INTO orders value ('21610', '2015-10-20', '356');
INSERT INTO orders value ('21613', '2015-10-21', '408');

INSERT INTO orders value ('21614', '2015-10-21', '282');

INSERT INTO orders value ('21617', '2015-10-23', '608');
INSERT INTO orders value ('21619', '2015-10-23', '148');

INSERT INTO orders value ('21623', '2015-10-23', '608');

填充order_line表

INSERT INTO order_line value ('21608', 'AT94', 11, 21.95);

INSERT INTO order_line value ('21610', 'DR93', 1, 495.00);

INSERT INTO order_line value ('21610', 'DW11', 1, 399.99);

INSERT INTO order_line value ('21613', 'KL62', 4, 329.95);

INSERT INTO order_line value ('21614', 'KT03', 2, 595.00);

INSERT INTO order_line value ('21617', 'BV06', 2, 794.95);

INSERT INTO order_line value ('21617', 'CD52', 4, 150.00);

INSERT INTO order_line value ('21619', 'DR93', 1, 495.00);

INSERT INTO order_line value ('21623', 'KV29', 2, 1290.00);

填充零件表

INSERT INTO part value ('AT94', 'Iron', 50, 'HW', '3', 24.95);

INSERT INTO part value ('BV06', 'Home Gym', 45, 'SG', '2', 794.95);

INSERT INTO part value ('CD52', 'Microwave Oven', 32, 'AP', '1', 165.00);

INSERT INTO part value ('DL71', 'Cordless Drill', 21, 'HW', '3', 129.95);

INSERT INTO part value ('DR93', 'Gas Range', 8, 'AP', '2', 495.00);

INSERT INTO part value ('DW11', 'Washer', 12, 'AP', '3', 399.99);

INSERT INTO part value ('FD21', 'Stand Mixer', 22, 'HW', '3', 159.95);

INSERT INTO part value ('KL62', 'Dryer', 12, 'AP', '1', 349.95);

INSERT INTO part value ('KT03', 'Dishwasher', 8, 'AP', '3', 595.00);

INSERT INTO part value ('KV29', 'Treadmill', 9, 'SG', '2', 1390.00);

Answer 1

你可以这样做。

 select customer.customer_num,customer.customer_name 
    from customer 
    where customer_id 
         in (SELECT rep_num   
                 from rep,customer  
                      where rep.rep_num = customer.rep_num   
                         and customer_num = 282)

Answer 2

尝试以下查询：

 SELECT customer.customer_num, customer.customer_name, rep.first_name 
    FROM rep 
    JOIN customer ON rep.rep_num = customer.rep_num
    WHERE rep.first_name = (Select rep.first_name FROM rep 
    JOIN customer ON rep.rep_num = customer.rep_num where customer.customer_num = 282);

或者，您可以将客户282的代表存储在变量中，并在where子句中使用它。通过这种方式，您可以在不使用如下的子查询的情况下在任何查询中重用该值：

SET @rep:= (Select rep.first_name FROM rep 
   inner JOIN customer ON rep.rep_num = customer.rep_num where customer.customer_num = 282);     

 SELECT customer.customer_num, customer.customer_name, rep.first_name 
        FROM rep 
        JOIN customer ON rep.rep_num = customer.rep_num
        WHERE rep.first_name = @rep;

希望它有所帮助！

在数据库中在MySQL中形成子查询

2 个答案: