mosh SQL 視頻課程
視頻鏈接：【中英字幕】一口氣看完！耗時(shí)100天打造SQL數(shù)據(jù)庫(kù)零基礎(chǔ)入門到精通全套教程_嗶哩嗶哩_bilibili
大神整理的視頻中使用到的數(shù)據(jù)庫(kù)：https://pan.baidu.com/s/1KMrI0NqCbWagKI_oK_Rndw?pwd=g5rp 提取碼: g5rp
知識(shí)點(diǎn)：
1、內(nèi)連接JOIN
2、外連接LEFT JOIN ON ,RIGHT JOIN ON,
JOIN USING (兩表中相同id)
3、交叉連接CROSS JOIN
UNION
4、新增數(shù)據(jù)INSERT INTO ... VALUES ...
5、更新數(shù)據(jù)UPDATE ... SET ...
6、刪除數(shù)據(jù)DELETE FROM ...WHERE
內(nèi)外連接效果對(duì)比
--內(nèi)連接，只返回符合條件的記錄
USE sql_store;
--
SELECT
o.order_id,
c.customer_id,
c.first_name
FROM orders o
JOIN customers c
ON o.customer_id = c.customer_id
ORDER BY c.customer_id
外連接
--left join right join
--結(jié)果中會(huì)顯示沒有訂單的 用戶信息 此時(shí)order_id 為null
USE sql_store;
SELECT
c.customer_id,
c.first_name,
o.order_id
FROM customers c
LEFT JOIN orders o
ON o.customer_id = c.customer_id
ORDER BY c.customer_id
練習(xí)
USE sql_store;
SELECT
p.product_id,
p.name,
oi.quantity
FROM products p
LEFT JOIN order_items oi
ON p.product_id= oi.product_id
ORDER BY p.product_id
兩次 left join
--使用建議，多單一的使用left join，避免與right join混用
USE sql_store;
SELECT
c.customer_id,
c.first_name,
o.order_id,
sh.name AS shipper
FROM customers c
LEFT JOIN orders o
ON o.customer_id = c.customer_id
LEFT JOIN shippers sh
ON o.shipper_id = sh.shipper_id
ORDER BY c.customer_id
練習(xí)
USE sql_store;
SELECT
o.order_date,
o.order_id,
c.first_name,
sh.name AS shipper,
os.name
FROM orders o
JOIN customers c
ON o.customer_id =c.customer_id
LEFT JOIN shippers sh
ON o.shipper_id= sh.shipper_id
LEFT JOIN order_statuses os
ON o.status =os.order_status_id
ORDER BY os.name
自連接
USE sql_hr;
SELECT
e.employee_id,
e.first_name,
m.first_name AS manager
FROM employees e
LEFT JOIN employees m
ON e.reports_to = m.employee_id
using (條件字段名)
--當(dāng)兩表格的條件字段相同時(shí)，使用此方法更簡(jiǎn)潔
--等同于 表1.條件字段名 = 表2.條件字段名
USE sql_store;
SELECT
o.order_id,
c.customer_id,
c.first_name
FROM orders o
JOIN customers c
-- ON o.customer_id = c.customer_id
USING (customer_id)
USE sql_store;
SELECT
*
FROM order_items oi
JOIN order_item_notes oin
ON oi.order_id =oin.order_id AND
oi.product_id = oin.product_id
---更改為
USE sql_store;
SELECT
*
FROM order_items oi
JOIN order_item_notes oin
USING (order_id,product_id)
練習(xí)
USE sql_invoicing;
SELECT
p.date,
c.name AS client,
p.amount,
pm.name AS payment_method
FROM payments p
JOIN clients c
USING (client_id)
JOIN payment_methods pm
ON p.payment_method=pm.payment_method_id
NATURAL JOIN
--根據(jù)相同id自動(dòng)連接，易出錯(cuò)
USE sql_store;
SELECT
*
FROM orders o
NATURAL JOIN customers c
交叉連接
--應(yīng)用場(chǎng)景，尺碼S、M衣服，對(duì)應(yīng)黑色，白色
--顯示語法，推薦，更明確
USE sql_store;
SELECT
c.first_name AS customer,
p.name AS product
FROM customers c
CROSS JOIN products p
ORDER BY c.first_name
--隱式連接
USE sql_store;
SELECT
c.first_name AS customer,
p.name AS product
FROM customers c,products p
-- CROSS JOIN products p,orders o
ORDER BY c.first_name
練習(xí)
--顯示連接
USE sql_store;
SELECT
sh.name AS shipper,
p.name AS product
FROM products p
CROSS JOIN shippers sh
ORDER BY sh.name
--隱式連接
USE sql_store;
SELECT
sh.name AS shipper,
p.name AS product
FROM products p,shippers sh
ORDER BY sh.name
USE sql_store;
SELECT
order_id,
order_date,
'Active' as status
FROM orders
WHERE order_date >='2019-01-01'
SELECT
order_id,
order_date,
'Archived' as status
FROM orders
WHERE order_date <'2019-01-01';
union
-- union
USE sql_store;
SELECT
order_id,
order_date,
'Active' as status
FROM orders
WHERE order_date >='2019-01-01'
UNION
SELECT
order_id,
order_date,
'Archived' as status
FROM orders
WHERE order_date <'2019-01-01'
--union不同表
USE sql_store;
SELECT first_name
FROM
customers
UNION
SELECT name
FROM shippers
練習(xí)
USE sql_store;
SELECT
customer_id,
first_name,
points,
'Bronze' AS type
FROM
customers
WHERE points<2000
UNION
SELECT
customer_id,
first_name,
points,
'Silver' AS type
FROM customers
WHERE points BETWEEN 2000 AND 3000
UNION
SELECT
customer_id,
first_name,
points,
'Gold' AS type
FROM customers
WHERE points>3000
ORDER BY first_name
-- ORDER BY只需要寫一遍，來排序
INSERT
#根據(jù)建表時(shí)設(shè)置的屬性來插入數(shù)據(jù)
USE sql_store;
INSERT INTO
customers
VALUES (
DEFAULT,
'fan',
'yx',
'1996-01-01',
NULL,
'adress',
'city',
'DZ',
DEFAULT
)
有默認(rèn)值的不賦值
use sql_store;
INSERT INTO customers
(
first_name,
last_name,
birth_date,
address,
city,
state
)
VALUES (
'aaa',
'bc',
'1990-01-01',
'sd',
'dz',
'la'
)
#一次性插入多條記錄
use sql_store;
INSERT INTO shippers
(
name
)
VALUES
('shipper1'),
('shipper2'),
('shipper3')
練習(xí)
#產(chǎn)品表中插入三條記錄
use sql_store;
INSERT INTO products
(
name,
quantity_in_stock,
unit_price
)
VALUES('aaa',2030,2.1),
('bbb',2000,1.2),
('ccc',3000,2.8)
將數(shù)據(jù)插入多個(gè)表
#場(chǎng)景：訂單表為父表，訂單明細(xì)表為子表
use sql_store;
INSERT INTO orders (customer_id,order_date,status)
VALUES
(1,'1992-01-01',1);
-查詢表中插入的最后一條記錄的ID
-SELECT LAST_INSERT_ID()
-為最后一條訂單新增2條訂單明細(xì)記錄
INSERT INTO order_items(order_id,product_id,quantity,unit_price)
VALUES(LAST_INSERT_ID(),1,1,1.2),
(LAST_INSERT_ID(),2,1,1.3)
新建副本，清空副本數(shù)據(jù)
use sql_store;
-- 創(chuàng)建表的副本
CREATE TABLE order_archived AS
SELECT * FROM orders
-- 該表無主鍵
-- 點(diǎn)擊刪除該表中的所有數(shù)據(jù)truncate table
#查詢符合條件的orders表數(shù)據(jù)，插入到附表中
use sql_store;
INSERT INTO order_archived
SELECT * FROM
orders
WHERE order_date<'2019-01-01'
練習(xí)
use sql_invoicing;
-- 創(chuàng)建表，并插入符合條件數(shù)據(jù)
CREATE TABLE invoice_archived
SELECT
i.invoice_id,
i.number,
c.name AS client,
i.invoice_total,
i.payment_total,
i.invoice_date,
i.due_date,
i.payment_date
-- i.invoice_date,i.due_date,i.payment_date發(fā)票表里僅有的字段，可省去i.以簡(jiǎn)化代碼
FROM
invoices i
JOIN clients c
USING (client_id)
WHERE payment_date IS NOT NULL
-- 運(yùn)行一次，運(yùn)行第二次會(huì)報(bào)錯(cuò)，提示表格已存在，可先drop table 再運(yùn)行以上代碼
更新表格中的記錄，一條
use sql_invoicing;
UPDATE invoices
SET payment_total='10',payment_date='2019-03-01'
WHERE invoice_id =1
記錄中將字段設(shè)置默認(rèn)值，設(shè)置空值
use sql_invoicing;
UPDATE invoices
SET payment_total=DEFAULT ,payment_date=NULL
WHERE invoice_id =1
算式更新記錄中的字段
use sql_invoicing;
UPDATE invoices
SET payment_total= invoice_total *0.5,
payment_date=due_date
WHERE invoice_id =3
更新多行記錄
#客戶id的記錄均更新
use sql_invoicing;
UPDATE invoices
SET payment_total= invoice_total *0.5,
payment_date=due_date
WHERE client_id =3
必須設(shè)置-以免后續(xù)報(bào)錯(cuò)
MySQL workbench設(shè)置
edit preferences-sql editor 取消safe updates選中
--where 中使用in
use sql_invoicing;
UPDATE invoices
SET payment_total= invoice_total *0.5,
payment_date=due_date
WHERE client_id in (3,4)
練習(xí)
use sql_store;
UPDATE customers
set points= points +50
WHERE birth_date < '1990-01-01'
--子查詢語句設(shè)置
use sql_invoicing;
UPDATE invoices
SET payment_total= invoice_total *0.5,
payment_date=due_date
WHERE client_id =
(SELECT client_id
FROM clients
WHERE name='Myworks')
use sql_invoicing;
UPDATE invoices
SET payment_total= invoice_total *0.5,
payment_date=due_date
WHERE client_id IN
(SELECT client_id
FROM clients
WHERE state IN ('CA','NY'))
use sql_invoicing;
UPDATE invoices
SET payment_total= invoice_total *0.5,
payment_date=due_date
WHERE payment_date IS NULL
練習(xí)
use sql_store;
UPDATE orders
SET comments='Gold'
WHERE customer_id IN
(SELECT customer_id
FROM
customers
WHERE points >3000
)
--
刪除
USE sql_invoicing;
DELETE FROM invoices
WHERE client_id =
(
SELECT client_id
FROM clients
WHERE name='Myworks'
)
