（1）你可以使用以下語句建立示例表：

mysql> CREATE TABLE shop (

 -> article INT(4) UNSIGNED ZEROFILL DEFAULT '0000' NOT NULL,

 -> dealer CHAR(20) DEFAULT '' NOT NULL,

 -> price DOUBLE(16,2) DEFAULT '0.00' NOT NULL,

 -> PRIMARY KEY(article, dealer));

mysql> INSERT INTO shop VALUES

 -> (1,'A',3.45),(1,'B',3.99),(2,'A',10.99),(3,'B',1.45),

 -> (3,'C',1.69),(3,'D',1.25),(4,'D',19.95);

（2）執行語句後，表應包含以下內容：SELECT * FROM shop;

（3）列的最大值

選取價格最貴：select max(price) as article from shop;

（4）擁有某個列的最大值的行

任務：找出最貴物品的編號、銷售商和價格。

方法一：

mysql> select article,dealer,price
-> from shop
-> where price=(select max(price) from shop);

方法二：按價格降序排序所有行並用MySQL特定LIMIT子句只得到第一行，這裡用到desc前面講過，是降序的意思。

mysql> select article ,dealer,price
-> from shop
-> order by price desc

-> limit 1;

注:如果有多項最貴的物品(例如每個的價格為19.95)，LIMIT解決方案僅僅顯示其中一個！

（5）列的最大值：按組

任務：每項物品的的最高價格是多少？

mysql> SELECT article, MAX(price) AS price
-> FROM shop
-> GROUP BY article
-> ;

（6）擁有某個欄位的組間最大值的行

任務：對每項物品，找出最貴价格的物品的經銷商。

SELECT article, dealer, price
FROM   shop s1
WHERE  price=(SELECT MAX(s2.price)
              FROM shop s2
              WHERE s1.article = s2.article);

（7）使用使用者變數

任務：要找出價格最高或最低的物品的

SELECT @min_price:=MIN(price),@max_price:=MAX(price) FROM shop;
SELECT * FROM shop WHERE price=@min_price OR price=@max_price;

（8）使用外來鍵

CREATE TABLE person (
    id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT,
    name CHAR(60) NOT NULL,
    PRIMARY KEY (id)
);

CREATE TABLE shirt (
    id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT,
    style ENUM('t-shirt', 'polo', 'dress') NOT NULL,
    color ENUM('red', 'blue', 'orange', 'white', 'black') NOT NULL,
    owner SMALLINT UNSIGNED NOT NULL REFERENCES person(id),
    PRIMARY KEY (id)
);

INSERT INTO person VALUES (NULL, 'Antonio Paz');

SELECT @last := LAST_INSERT_ID();

INSERT INTO shirt VALUES
(NULL, 'polo', 'blue', @last),
(NULL, 'dress', 'white', @last),
(NULL, 't-shirt', 'blue', @last);

INSERT INTO person VALUES (NULL, 'Lilliana Angelovska');

SELECT @last := LAST_INSERT_ID();

INSERT INTO shirt VALUES
(NULL, 'dress', 'orange', @last),
(NULL, 'polo', 'red', @last),
(NULL, 'dress', 'blue', @last),
(NULL, 't-shirt', 'white', @last);

SELECT * FROM person;

SELECT * FROM shirt;

SELECT s.* FROM person p, shirt s
 WHERE p.name LIKE 'Lilliana%'
   AND s.owner = p.id
   AND s.color <> 'white';

（8）根據天計算訪問量

CREATE TABLE t1 (year YEAR(4), month INT(2) UNSIGNED ZEROFILL,
             day INT(2) UNSIGNED ZEROFILL);
INSERT INTO t1 VALUES(2000,1,1),(2000,1,20),(2000,1,30),(2000,2,2),
            (2000,2,23),(2000,2,23);

SELECT year,month,BIT_COUNT(BIT_OR(1<<day)) AS days FROM t1
       GROUP BY year,month;

（9）使用AUTO_INCREMENT

CREATE TABLE animals (
     id MEDIUMINT NOT NULL AUTO_INCREMENT,
     name CHAR(30) NOT NULL,
     PRIMARY KEY (id)
 );

INSERT INTO animals (name) VALUES 
    ('dog'),('cat'),('penguin'),
    ('lax'),('whale'),('ostrich');

SELECT * FROM animals;

本文來自部落格園，作者：川川菜鳥，轉載請註明原文連結：https://www.cnblogs.com/aisisi/p/15058584.html