SQL语法实践（一）：基础语法-优快云博客

本文链接：https://blog.youkuaiyun.com/uxiang_blog/article/details/134195468

本文详细介绍了SQL中的基本操作，包括创建表结构、插入数据、查询特定条件、去重、筛选、排序、更新和删除等，以及使用LIKE、IN和BETWEEN等关键字进行数据过滤。

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文章

实践

CREATE TABLE friend(
    fid INT NOT NULL,
    NAME VARCHAR(10) NOT NULL,
    age INT NOT NULL,
    adress VARCHAR(10)
)

SHOW TABLES;
SELECT * FROM friend;
SELECT fid,NAME FROM friend;

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INSERT INTO friend VALUES(1,'Jack',18,'Tianjing');
INSERT INTO friend VALUES(2,'Liming',17,'Beijing');
INSERT INTO friend (fid, NAME, age,adress) VALUES (3,'Zhangwei',22,'Wuhan');
INSERT INTO friend (fid,NAME,age) VALUES (4,'Wangmei',17);
INSERT INTO friend VALUES(5,'Lihua',18,'Shanghei'),
                         (6,'Wangyang',18,'Shanxi');                       
INSERT INTO friend VALUES(7,'Penchen',19,'Beijing'),
                         (8,'Yenuoyi',20,'Wuhan');

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SELECT DISTINCT adress FROM friend;

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SELECT age FROM friend WHERE age>18;
SELECT * FROM friend WHERE age>18;
SELECT * FROM friend WHERE age>18 AND adress='Wuhan';
SELECT * FROM friend WHERE age<18 OR adress='Beijing';
SELECT * FROM friend WHERE (age<20 AND NAME='Jack') OR adress='Tianjing';

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SELECT * FROM friend ORDER BY adress ASC; 
SELECT * FROM friend ORDER BY age DESC;

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UPDATE friend SET adress='Chengdu' WHERE fid=4; 
UPDATE friend SET adress='Sichuan' WHERE NAME='Wangmei';  
UPDATE friend SET age=18 WHERE adress='Wuhan';

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DELETE FROM friend WHERE fid=8

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SELECT * FROM student; 
TRUNCATE TABLE student; 
SELECT * FROM student;

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SELECT * FROM student; 
DROP TABLE student; 
SELECT * FROM student;

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SELECT * FROM friend;
SELECT * FROM friend WHERE NAME LIKE 'L%';   
SELECT * FROM friend WHERE adress LIKE '%g'; 
SELECT * FROM friend WHERE adress NOT LIKE '%ng%';

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SELECT * FROM friend;
SELECT * FROM friend WHERE adress IN('Wuhan','Shanghei');
SELECT adress FROM friend WHERE adress IN('wuhan','shanghei');

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SELECT * FROM friend WHERE fid BETWEEN 1 AND 5;

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SELECT * FROM friend ORDER BY adress ASC;
SELECT * FROM friend WHERE adress BETWEEN 'chengdu' AND 'tianjing';

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总结

一些术语解释

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附上代码

//创建表
CREATE TABLE friend(
    fid INT NOT NULL,
    NAME VARCHAR(10) NOT NULL,
    age INT NOT NULL,
    adress VARCHAR(10)
)ENGINE=INNODB;

//select
SHOW TABLES;
SELECT * FROM friend;
SELECT fid,NAME FROM friend;

//insert
INSERT INTO friend VALUES(1,'Jack',18,'Tianjing');
INSERT INTO friend VALUES(2,'Liming',17,'Beijing');
INSERT INTO friend (fid, NAME, age,adress) VALUES (3,'Zhangwei',22,'Wuhan');
INSERT INTO friend (fid,NAME,age) VALUES (4,'Wangmei',17);
INSERT INTO friend VALUES(5,'Lihua',18,'Shanghei'),
                         (6,'Wangyang',18,'Shanxi');                       
INSERT INTO friend VALUES(7,'Penchen',19,'Beijing'),
                         (8,'Yenuoyi',20,'Wuhan');                       
                         
//distinct去重                        
SELECT DISTINCT adress FROM friend;  

//where约束
SELECT age FROM friend WHERE age>18;
SELECT * FROM friend WHERE age>18;
SELECT * FROM friend WHERE age>18 AND adress='Wuhan';
SELECT * FROM friend WHERE age<18 OR adress='Beijing';
SELECT * FROM friend WHERE (age<20 AND NAME='Jack') OR adress='Tianjing';
 
//order by 排序                
SELECT * FROM friend ORDER BY adress ASC; 
SELECT * FROM friend ORDER BY age DESC;

//update修改 
UPDATE friend SET adress='Chengdu' WHERE fid=4; 
UPDATE friend SET adress='Sichuan' WHERE NAME='Wangmei'; 
UPDATE friend SET age=18 WHERE adress='Wuhan';                   
                         
//delete删除行                        
DELETE FROM friend WHERE fid=8; 

//truncate 清除数据
TRUNCATE TABLE student; 
SELECT * FROM student; 
DROP TABLE student; 
SELECT * FROM student; 
                    
//like                        
SELECT * FROM friend;
SELECT * FROM friend WHERE NAME LIKE 'L%'; 
SELECT * FROM friend WHERE adress LIKE '%g';
SELECT * FROM friend WHERE adress NOT LIKE '%ng%';

//in
SELECT * FROM friend WHERE adress IN('Wuhan','Shanghei');
SELECT adress FROM friend WHERE adress IN('wuhan','shanghei');

//and
SELECT * FROM friend WHERE fid BETWEEN 1 AND 5;
SELECT * FROM friend ORDER BY adress ASC;
SELECT * FROM friend WHERE adress BETWEEN 'chengdu' AND 'tianjing';                     
SELECT * FROM friend WHERE adress BETWEEN(LIKE 'B%') AND (LIKE 'D%');  /*false*/             

//as别名
SELECT * FROM friend AS partner;
SELECT * FROM friend parner;
SELECT * FROM friend parner WHERE partner.adress='Shanghei'; /*false*/

SELECT * FROM friend adress AS place; /*false*/
SELECT adress AS place FROM friend;
SELECT adress place FROM friend;



CREATE TABLE `rock_sql`.`colleague`( `sid` INT(10) NOT NULL AUTO_INCREMENT, 
    `name` VARCHAR(50),
    `adress` VARCHAR(50), 
    `phone` INT(15), 
    `age` INT(10), 
    `major` VARCHAR(50), 
    PRIMARY KEY (`sid`)
) ENGINE=INNODB CHARSET=utf8 COLLATE=utf8_general_ci; 

SHOW FULL TABLES FROM `rock_sql` WHERE table_type = 'BASE TABLE';  
SHOW CHARSET; 
SHOW TABLE STATUS FROM `rock_sql` LIKE 'colleague'; 
SHOW CHARSET; 
SHOW FULL FIELDS FROM `rock_sql`.`colleague`; 
SHOW KEYS FROM `rock_sql`.`colleague` ; 
SHOW COLLATION;