第三章

第一节. 列属性| Column Attributes[插入，更新和删除数据]

## VARCHAR(50) = 字符串 （最多50个）
## PK = primary key（主键）
## NN = Not NULL （非空值）
## AI = Auto Increment （自动递增）
## Default/Expression = 默认值

第二节. 插入单行| Inserting a Row

INSERT INTO customers
VALUES (DEFAULT, 'John', 'Smith', '1990-01-01', DEFAULT, 'ADDRESS', 'city', 'CA', DEFAULT)

第三节. 插入多行| Inserting Multiple Row

INSERT INTO shippers (name)
VALUES ('Shipper1'),
       ('Shipper2'),
       ('shipper3')

第三节.作业练习

INSERT INTO products (name, quantity_in_stock, unit_price)
VALUES ('product1', 5, 1.95),
       ('product2', 6, 1.95),
       ('product3', 7, 1.95)

第四节. 插入分层行| Inserting Hierachical Rows

INSERT INTO orders (customer_id, order_date, status)
VALUES (1, '2019-01-02', 1);

INSERT INTO order_items
VALUES 
      (LAST_INSERT_ID(), 1, 1, 2.95),
      (LAST_INSERT_ID(), 2, 1, 3.95)

第五节. 创建表复制| Creating a copy of a table

CREATE TABLE orders_archived AS
SELECT * FROM orders


INSERT INTO orders_archived()
SELECT *
FROM orders
WHERE order_date < '2019-01-01'

第五节. 作业练习

USE sql_invoicing;

SELECT 
      i.invoice_id,
      i.number,
      c.name AS client,
      i.invoice_total,
      i.payment_total,
      i.invoice_Date,
      i.payment_date,
      i.due_Date
FROM invoices i
JOIN clients c
   USING (client_id)

第六节. 更新单行| Updating a Single Row

UPDATE invoices
SET payment_total = 10, payment_date = '2019-03-01'
WHERE invoice_id = 1

第七节. 更新多行| Updating Multiple Rows

UPDATE invoices
SET
   payment_total = invoice_total * 0.5,
   payment_date = due_date
WHERE client_id IN (3,4)

第七节. 作业练习

USE sql_Store;

UPDATE customers
SET points = points +50
WHERE birth_date < '1990-01-01'

第八节. 在Updates中用子查询|Using Subqueries in Updates

USE sql_invoicing;

UPDATE invoices
SET
   payment_total = invoice_total * 0.5,
   payment_date = due_date
WHERE client_id = 
                (SELECT client_id
                 FROM clients
				 WHERER name = 'Myworks')

第九节. 删除行|Deleting Rows

DELETE FROM invoices
WHERE client_id = (
       SELECT *
       FROM clients
       WHERE name = 'Myworks'
)

第十节. 恢复数据库|Restoring the Databases

## FILE ---->  Open SQL Script----->找到自己的数据并导入

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