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  • SQL的学习

    SQL的学习之路,主要参考资料是:

    1. SQL必知必会
    2. W3school的SQL简介

    操作使用的数据库为Access及MySQL。

    数据采用的是SQL必知必会中的数据(最下方可以下载数据)。其有5个表,表的关系如下:

      1 # 这里补充下,MySQL创建该数据库(2017.5.17),复制到MySQL创建执行创建即可(数据来源于《SQL必知必会》);
      2 
      3 -- ----------------------
      4 -- Create Customers table
      5 -- ----------------------
      6 CREATE TABLE Customers
      7 (
      8   cust_id      char(10)  NOT NULL ,
      9   cust_name    char(50)  NOT NULL ,
     10   cust_address char(50)  NULL ,
     11   cust_city    char(50)  NULL ,
     12   cust_state   char(5)   NULL ,
     13   cust_zip     char(10)  NULL ,
     14   cust_country char(50)  NULL ,
     15   cust_contact char(50)  NULL ,
     16   cust_email   char(255) NULL 
     17 );
     18 
     19 -- -----------------------
     20 -- Create OrderItems table
     21 -- -----------------------
     22 CREATE TABLE OrderItems
     23 (
     24   order_num  int          NOT NULL ,
     25   order_item int          NOT NULL ,
     26   prod_id    char(10)     NOT NULL ,
     27   quantity   int          NOT NULL ,
     28   item_price decimal(8,2) NOT NULL 
     29 );
     30 
     31 
     32 -- -------------------
     33 -- Create Orders table
     34 -- -------------------
     35 CREATE TABLE Orders
     36 (
     37   order_num  int      NOT NULL ,
     38   order_date datetime NOT NULL ,
     39   cust_id    char(10) NOT NULL 
     40 );
     41 
     42 -- ---------------------
     43 -- Create Products table
     44 -- ---------------------
     45 CREATE TABLE Products
     46 (
     47   prod_id    char(10)      NOT NULL ,
     48   vend_id    char(10)      NOT NULL ,
     49   prod_name  char(255)     NOT NULL ,
     50   prod_price decimal(8,2)  NOT NULL ,
     51   prod_desc  text          NULL 
     52 );
     53 
     54 -- --------------------
     55 -- Create Vendors table
     56 -- --------------------
     57 CREATE TABLE Vendors
     58 (
     59   vend_id      char(10) NOT NULL ,
     60   vend_name    char(50) NOT NULL ,
     61   vend_address char(50) NULL ,
     62   vend_city    char(50) NULL ,
     63   vend_state   char(5)  NULL ,
     64   vend_zip     char(10) NULL ,
     65   vend_country char(50) NULL 
     66 );
     67 
     68 
     69 -- -------------------
     70 -- Define primary keys
     71 -- -------------------
     72 ALTER TABLE Customers ADD PRIMARY KEY (cust_id);
     73 ALTER TABLE OrderItems ADD PRIMARY KEY (order_num, order_item);
     74 ALTER TABLE Orders ADD PRIMARY KEY (order_num);
     75 ALTER TABLE Products ADD PRIMARY KEY (prod_id);
     76 ALTER TABLE Vendors ADD PRIMARY KEY (vend_id);
     77 
     78 
     79 -- -------------------
     80 -- Define foreign keys
     81 -- -------------------
     82 ALTER TABLE OrderItems ADD CONSTRAINT FK_OrderItems_Orders FOREIGN KEY (order_num) REFERENCES Orders (order_num);
     83 ALTER TABLE OrderItems ADD CONSTRAINT FK_OrderItems_Products FOREIGN KEY (prod_id) REFERENCES Products (prod_id);
     84 ALTER TABLE Orders ADD CONSTRAINT FK_Orders_Customers FOREIGN KEY (cust_id) REFERENCES Customers (cust_id);
     85 ALTER TABLE Products ADD CONSTRAINT FK_Products_Vendors FOREIGN KEY (vend_id) REFERENCES Vendors (vend_id);
     86 
     87 # 插入数据
     88 -- ------------------------
     89 -- Populate Customers table
     90 -- ------------------------
     91 INSERT INTO Customers(cust_id, cust_name, cust_address, cust_city, cust_state, cust_zip, cust_country, cust_contact, cust_email)
     92 VALUES('1000000001', 'Village Toys', '200 Maple Lane', 'Detroit', 'MI', '44444', 'USA', 'John Smith', 'sales@villagetoys.com');
     93 INSERT INTO Customers(cust_id, cust_name, cust_address, cust_city, cust_state, cust_zip, cust_country, cust_contact)
     94 VALUES('1000000002', 'Kids Place', '333 South Lake Drive', 'Columbus', 'OH', '43333', 'USA', 'Michelle Green');
     95 INSERT INTO Customers(cust_id, cust_name, cust_address, cust_city, cust_state, cust_zip, cust_country, cust_contact, cust_email)
     96 VALUES('1000000003', 'Fun4All', '1 Sunny Place', 'Muncie', 'IN', '42222', 'USA', 'Jim Jones', 'jjones@fun4all.com');
     97 INSERT INTO Customers(cust_id, cust_name, cust_address, cust_city, cust_state, cust_zip, cust_country, cust_contact, cust_email)
     98 VALUES('1000000004', 'Fun4All', '829 Riverside Drive', 'Phoenix', 'AZ', '88888', 'USA', 'Denise L. Stephens', 'dstephens@fun4all.com');
     99 INSERT INTO Customers(cust_id, cust_name, cust_address, cust_city, cust_state, cust_zip, cust_country, cust_contact)
    100 VALUES('1000000005', 'The Toy Store', '4545 53rd Street', 'Chicago', 'IL', '54545', 'USA', 'Kim Howard');
    101 
    102 -- ----------------------
    103 -- Populate Vendors table
    104 -- ----------------------
    105 INSERT INTO Vendors(vend_id, vend_name, vend_address, vend_city, vend_state, vend_zip, vend_country)
    106 VALUES('BRS01','Bears R Us','123 Main Street','Bear Town','MI','44444', 'USA');
    107 INSERT INTO Vendors(vend_id, vend_name, vend_address, vend_city, vend_state, vend_zip, vend_country)
    108 VALUES('BRE02','Bear Emporium','500 Park Street','Anytown','OH','44333', 'USA');
    109 INSERT INTO Vendors(vend_id, vend_name, vend_address, vend_city, vend_state, vend_zip, vend_country)
    110 VALUES('DLL01','Doll House Inc.','555 High Street','Dollsville','CA','99999', 'USA');
    111 INSERT INTO Vendors(vend_id, vend_name, vend_address, vend_city, vend_state, vend_zip, vend_country)
    112 VALUES('FRB01','Furball Inc.','1000 5th Avenue','New York','NY','11111', 'USA');
    113 INSERT INTO Vendors(vend_id, vend_name, vend_address, vend_city, vend_state, vend_zip, vend_country)
    114 VALUES('FNG01','Fun and Games','42 Galaxy Road','London', NULL,'N16 6PS', 'England');
    115 INSERT INTO Vendors(vend_id, vend_name, vend_address, vend_city, vend_state, vend_zip, vend_country)
    116 VALUES('JTS01','Jouets et ours','1 Rue Amusement','Paris', NULL,'45678', 'France');
    117 
    118 -- -----------------------
    119 -- Populate Products table
    120 -- -----------------------
    121 INSERT INTO Products(prod_id, vend_id, prod_name, prod_price, prod_desc)
    122 VALUES('BR01', 'BRS01', '8 inch teddy bear', 5.99, '8 inch teddy bear, comes with cap and jacket');
    123 INSERT INTO Products(prod_id, vend_id, prod_name, prod_price, prod_desc)
    124 VALUES('BR02', 'BRS01', '12 inch teddy bear', 8.99, '12 inch teddy bear, comes with cap and jacket');
    125 INSERT INTO Products(prod_id, vend_id, prod_name, prod_price, prod_desc)
    126 VALUES('BR03', 'BRS01', '18 inch teddy bear', 11.99, '18 inch teddy bear, comes with cap and jacket');
    127 INSERT INTO Products(prod_id, vend_id, prod_name, prod_price, prod_desc)
    128 VALUES('BNBG01', 'DLL01', 'Fish bean bag toy', 3.49, 'Fish bean bag toy, complete with bean bag worms with which to feed it');
    129 INSERT INTO Products(prod_id, vend_id, prod_name, prod_price, prod_desc)
    130 VALUES('BNBG02', 'DLL01', 'Bird bean bag toy', 3.49, 'Bird bean bag toy, eggs are not included');
    131 INSERT INTO Products(prod_id, vend_id, prod_name, prod_price, prod_desc)
    132 VALUES('BNBG03', 'DLL01', 'Rabbit bean bag toy', 3.49, 'Rabbit bean bag toy, comes with bean bag carrots');
    133 INSERT INTO Products(prod_id, vend_id, prod_name, prod_price, prod_desc)
    134 VALUES('RGAN01', 'DLL01', 'Raggedy Ann', 4.99, '18 inch Raggedy Ann doll');
    135 INSERT INTO Products(prod_id, vend_id, prod_name, prod_price, prod_desc)
    136 VALUES('RYL01', 'FNG01', 'King doll', 9.49, '12 inch king doll with royal garments and crown');
    137 INSERT INTO Products(prod_id, vend_id, prod_name, prod_price, prod_desc)
    138 VALUES('RYL02', 'FNG01', 'Queen doll', 9.49, '12 inch queen doll with royal garments and crown');
    139 
    140 -- ---------------------
    141 -- Populate Orders table
    142 -- ---------------------
    143 INSERT INTO Orders(order_num, order_date, cust_id)
    144 VALUES(20005, '2012-05-01', '1000000001');
    145 INSERT INTO Orders(order_num, order_date, cust_id)
    146 VALUES(20006, '2012-01-12', '1000000003');
    147 INSERT INTO Orders(order_num, order_date, cust_id)
    148 VALUES(20007, '2012-01-30', '1000000004');
    149 INSERT INTO Orders(order_num, order_date, cust_id)
    150 VALUES(20008, '2012-02-03', '1000000005');
    151 INSERT INTO Orders(order_num, order_date, cust_id)
    152 VALUES(20009, '2012-02-08', '1000000001');
    153 
    154 -- -------------------------
    155 -- Populate OrderItems table
    156 -- -------------------------
    157 INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
    158 VALUES(20005, 1, 'BR01', 100, 5.49);
    159 INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
    160 VALUES(20005, 2, 'BR03', 100, 10.99);
    161 INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
    162 VALUES(20006, 1, 'BR01', 20, 5.99);
    163 INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
    164 VALUES(20006, 2, 'BR02', 10, 8.99);
    165 INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
    166 VALUES(20006, 3, 'BR03', 10, 11.99);
    167 INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
    168 VALUES(20007, 1, 'BR03', 50, 11.49);
    169 INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
    170 VALUES(20007, 2, 'BNBG01', 100, 2.99);
    171 INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
    172 VALUES(20007, 3, 'BNBG02', 100, 2.99);
    173 INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
    174 VALUES(20007, 4, 'BNBG03', 100, 2.99);
    175 INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
    176 VALUES(20007, 5, 'RGAN01', 50, 4.49);
    177 INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
    178 VALUES(20008, 1, 'RGAN01', 5, 4.99);
    179 INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
    180 VALUES(20008, 2, 'BR03', 5, 11.99);
    181 INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
    182 VALUES(20008, 3, 'BNBG01', 10, 3.49);
    183 INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
    184 VALUES(20008, 4, 'BNBG02', 10, 3.49);
    185 INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
    186 VALUES(20008, 5, 'BNBG03', 10, 3.49);
    187 INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
    188 VALUES(20009, 1, 'BNBG01', 250, 2.49);
    189 INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
    190 VALUES(20009, 2, 'BNBG02', 250, 2.49);
    191 INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
    192 VALUES(20009, 3, 'BNBG03', 250, 2.49);
    创建表及插入数据

    看不清的图片:右击新标签页打开即可。


    1.SQL基础

    2.检索数据


     

    #SQL对大小写不敏感
    #检索单个列
    SELECT prod_name
    FROM products;
    #检索多个列
    SELECT prod_name,prod_id,prod_price
    FROM products;
    #检索多个列
    SELECT *
    FROM products;
    #检索不同的值
    SELECT DISTINCT vend_id
    FROM products;
    #限制结果,需要好好理解
    SELECT prod_name
    FROM products
    LIMIT 5;
    SELECT prod_name
    FROM products
    LIMIT 4 OFFSET 5;#4是检索的行数,5是从那儿开始
    SELECT prod_name
    FROM products
    LIMIT 5,2;#逗号前,从哪儿开始,逗号后,检索行数

    3.排序检索数据

     

    #排序检索
    SELECT prod_name
    FROM products
    ORDER BY prod_name;
    #多个列
    SELECT prod_id,prod_price,prod_name
    FROM products
    ORDER BY prod_price,prod_name;
    #按照列的相对位置
    SELECT prod_id,prod_price,prod_name
    FROM products
    ORDER BY 2,3;
    #混合使用
    SELECT prod_id,prod_price,prod_name
    FROM products
    ORDER BY 2,vend_id;
    #降序
    SELECT prod_id,prod_price,prod_name
    FROM products
    ORDER BY prod_price DESC;
    #多个列降序
    SELECT prod_id,prod_price,prod_name
    FROM products
    ORDER BY prod_price DESC,prod_name DESC;

     

     

    4.过滤数据

     

    #where子句过滤数据
    SELECT prod_name,prod_price
    FROM products
    WHERE prod_price = 3.49;
    SELECT prod_name,prod_price
    FROM products
    WHERE prod_price > 3.49
    ORDER BY prod_price DESC;
    #不匹配检查
    SELECT vend_id,prod_name
    FROM products
    WHERE vend_id != 'DLL01';
    #范围值
    SELECT prod_name,prod_price
    FROM products
    WHERE prod_price BETWEEN 5 AND 10;
    #空值检查
    SELECT cust_name
    FROM customers
    WHERE cust_email IS NULL;

     

     

     

    5.高级过滤

    #组合where子句
    SELECT prod_id,prod_price,prod_name
    FROM products
    WHERE vend_id = "DLL01" AND prod_price <= 4
    ORDER BY prod_name;
    
    SELECT prod_name,prod_price
    FROM products
    WHERE vend_id = "DLL01" OR vend_id = "BRS01";
    #优先级
    SELECT prod_name,prod_price
    FROM products
    WHERE vend_id = "DLL01" OR vend_id = "BRS01" AND prod_price >=10;
    
    SELECT prod_name,prod_price
    FROM products
    WHERE (vend_id = "DLL01" OR vend_id = "BRS01") AND prod_price >=10;
    #in
    SELECT prod_name,prod_price
    FROM products
    WHERE vend_id IN ('DLL01','BRS01')
    ORDER BY prod_name;
    
    SELECT prod_name,prod_price
    FROM products
    WHERE vend_id = 'DLL01' OR vend_id = 'BRS01';
    
    SELECT prod_name,prod_price
    FROM products
    WHERE vend_id IN ('DLL01','BRS01') AND prod_price >= 10;
    #not
    SELECT prod_name,prod_price
    FROM products
    WHERE NOT vend_id ="DLL01"
    ORDER BY prod_name;
    
    SELECT prod_name,prod_price
    FROM products
    WHERE vend_id <> 'DLL01'
    ORDER BY prod_name;
    
    SELECT prod_name,prod_price
    FROM products
    WHERE NOT vend_id IN ('DLL01','BRS01') AND prod_price >= 5;

    6.通配符过滤

     

    #不区分大小写,但是区分空格
    SELECT prod_id,prod_name
    FROM products
    WHERE prod_name LIKE 'Fish%';
    SELECT prod_id,prod_name FROM products WHERE prod_name LIKE "%bean bag%";
    SELECT prod_id,prod_name FROM products WHERE prod_name LIKE 'F%y';
    SELECT cust_email FROM customers WHERE cust_email LIKE '%@fun4all.com'; #%可以匹配空格,但是不能匹配NULL #x下划线 SELECT prod_id,prod_name FROM products WHERE prod_name LIKE '__ inch teddy bear'; SELECT prod_id,prod_name FROM products WHERE prod_name LIKE '% inch teddy bear';

     

     

     

    7.创建计算字段

    8.函数特性

    9.函数

     

    10.汇总数据

    11.分组数据

     

    12.子查询

    这里说白了就是select语句嵌套,如select * from (select cust_name from customers)

    13.联结 

    笛卡尔积

     所谓的表的联结,其实就是将几个表的信息综合到一起,进而成为一个表。而这种综合其实是通过这几个表相同的主键,或者列,来进行选择。

    14.高级联结

     

    如果3个以上的表,那怎样联结?

     

    1. 3个

     

    1 use test;
    2 select cust_name,cust_contact
    3 from (customers 
    4 inner join orders
    5 on customers.cust_id = orders.cust_id)
    6 inner join orderitems 
    7 on orderitems.order_num = orders.order_num;

     

    语法可以概括为:

     

    FROM (表1 INNER JOIN 表2 ON 表1.字段号=表2.字段号) INNER JOIN 表3 ON 表1.字段号=表3.字段号

     

    2. 同理,4个表可以概括为:

     

    FROM ((表1 INNER JOIN 表2 ON 表1.字段号=表2.字段号) INNER JOIN 表3 ON 表1.字段号=表3.字段号) INNER JOIN 表4 ON Member.字段号=表4.字段号

     

    15.组合查询

    关于规则中列顺序,前后必须一致否则会出现如下情况:

    1 use test;
    2 select cust_name ,cust_email,cust_contact
    3 from customers
    4 where cust_state in ('IL','IN','MI')
    5 union all
    6 select cust_name,cust_contact,cust_email
    7 from customers
    8 where cust_name = 'Fun4All'

    返回结果为:

     
    cust_name cust_email cust_contact
    Village Toys sales@villagetoys.com John Smith
    Fun4All jjones@fun4all.com Jim Jones
    The Toy Store   Kim Howard
    Fun4All Jim Jones jjones@fun4all.com
    Fun4All Denise L. Stephens dstephens@fun4all.com

    列的顺序一致,才会返回正确结果

    1 use test;
    2 select cust_name ,cust_email,cust_contact
    3 from customers
    4 where cust_state in ('IL','IN','MI')
    5 union all
    6 select cust_name,cust_email,cust_contact
    7 from customers
    8 where cust_name = 'Fun4All'

    结果:

    cust_name  cust_email cust_contact
    Village Toys sales@villagetoys.com John Smith
    Fun4All jjones@fun4all.com Jim Jones
    The Toy Store   Kim Howard
    Fun4All jjones@fun4all.com Jim Jones
    Fun4All dstephens@fun4all.com Denise L. Stephens

    16.插入数据

    INSERT SELECT:

    它可以将SELCET语句结果插入表中,在某种意义上可以完成表的复制

    如:

     1 USE test;#使用数据库test
     2 CREATE TABLE CustNew
     3 (
     4   cust_id      char(10)  NOT NULL ,
     5   cust_name    char(50)  NOT NULL ,
     6   cust_address char(50)  NULL ,
     7   cust_city    char(50)  NULL ,
     8   cust_state   char(5)   NULL ,
     9   cust_zip     char(10)  NULL ,
    10   cust_country char(50)  NULL ,
    11   cust_contact char(50)  NULL ,
    12   cust_email   char(255) NULL 
    13 );#创新新表
    14 INSERT INTO CustNew
    15 (
    16 cust_id,
    17 cust_name,
    18 cust_address,
    19 cust_city,
    20 cust_state,
    21 cust_zip,
    22 cust_country,
    23 cust_contact,
    24 cust_email
    25 )
    26 SELECT 
    27 cust_id,
    28 cust_name,
    29 cust_address,
    30 cust_city,
    31 cust_state,
    32 cust_zip,
    33 cust_country,
    34 cust_contact,
    35 cust_email
    36 FROM customers;#将customers表的数据插入新表alter
    37 SELECT * FROM CustNew;

    返回结果如下:

     

     而如果反过来用,大概就是:

    1 insert into
    2 customers
    3 (列1,列2,......)
    4  select 
    5 列1,列2,.....
    6  from custnew

    即可完成将表custnew中的数据全部插入customers,这也完成了一条insert插入多条数据。

    通常,一条INSERT 语句,只能插入一行数据,要插入多行,就必须执行多个INSERT,但是, INSERT SELECT 是个例外。

    以上方法的复制,实际上是重新在数据库中创建了一个新表。

    SELECT INTO:

    这种方法,可以在SQL语句运行中创建一个表,并将一个表复制到这个全新的表。

    我们可以在实验新的SQL语句前,用其进行复制,这样就不影响到实际数据。

    如:

    USE test;#使用数据库
    CREATE TABLE Cucopy as
    SELECT * FROM customers;#复制
    SELECT * FROM Cucopy;

     返回结果,与上表一致。

     17.更新和删除

    18.创建和操纵表

    这里中点说一下创建表时,指定默认值的问题。一般来说,创建表时,我们需要指定列的数据类型、是否NULL列。关于NULL值具体说明请看下图。

    默认值要是用的好,可以省却我们很多时间。

    因其经常用于指定默认日期,这里以日期为例。

    首先,在MySQL中内建的日期函数:

    函数描述
    NOW() 返回当前的日期和时间
    CURDATE() 返回当前的日期
    CURTIME() 返回当前的时间
    DATE() 提取日期或日期/时间表达式的日期部分
    EXTRACT() 返回日期/时间按的单独部分
    DATE_ADD() 给日期添加指定的时间间隔
    DATE_SUB() 从日期减去指定的时间间隔
    DATEDIFF() 返回两个日期之间的天数
    DATE_FORMAT() 用不同的格式显示日期/时间

    创建数据库t2,插入表。如下:

    CREATE DATABASE t2;
    USE t2;
    CREATE TABLE test
    (id int(5) NOT NULL,
    noedate timestamp NOT NULL DEFAULT current_timestamp()
    );

    调用如下:

    USE t2;
    INSERT INTO test(id)
    values(1);
    SELET * FROM test;

    返回结果:

    id nowdate
    1 2017-05-08 22:09:45

    以下SQL不合法:

    --time_d time NOT NULL DEFAULT CURTIME(), 
    --date_e date NOT NULL DEFAULT CURDATE(), 
    --datetime_f datetime NOT NULL DEFAULT NOW(), 

    DATETIME类型:NOW()函数以'YYYY-MM-DD HH:MM:SS'返回当前的日期时间,可以直接存到DATETIME字段中。不支持使用系统默认值。 

    DATE类型:CURDATE()以'YYYY-MM-DD'的格式返回今天的日期,可以直接存到DATE字段中。不支持使用系统默认值。 

    TIME类型:CURTIME()以'HH:MM:SS'的格式返回当前的时间,可以直接存到TIME字段中。不支持使用系统默认值。 

    常见错误:

    CREATE TABLE dnt_forums
    ( 
    aa int NOT NULL DEFAULT (''), 
    bb date NOT NULL DEFAULT (getdate()), 
    cc char(50) NOT NULL DEFAULT (null) 
    );

    aa 是 int 类型,默认值也得是整型,并且default后边不要()括号 。
    bb date类型不支持使用系统默认值,改成timestamp,能过now()取系统时间 。
    cc 已经不允许为空(not null)所以不能默认为 null ,可以改成空字符串 。

    修改:

    CREATE TABLE dnt_forums( 
    aa int NOT NULL DEFAULT 2, 
    bb timestamp NOT NULL DEFAULT now(), 
    cc char(50) NOT NULL DEFAULT '' 
    ); 

    这个日期问题,依然有很多不太明白的地方,以后学习过程碰到继续解决。

    主要参考:

    脚本之家博客

    重命名表:

    RENAME TABLE  cucopy1 TO hi;

     删除表:

    DROP TABLE hi;
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  • 原文地址:https://www.cnblogs.com/sunshinewang/p/6789419.html
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