2023-11-12第11章_数据处理之增删改
2023-11-19 本文已影响0人
大也
-- 1.INSERT INTO
-- INSERT INTO users(id,userid,department_id)
-- VALUES
-- (1,'Rpatel',10),
-- (2,'Bdancs',10),
-- (3,'Bbiri',20),
-- (4,'Cnewman',30),
-- (5,'Aropebur',40);
-- 2.UPDATE ... SET ,连接 'Claws' IS NOT NULL;
-- UPDATE pet SET owner = 'kevin',species = 'Bird'
-- WHERE pet.name = 'Claws';
-- 3. DELETE FROM ... 有参数 删行数据 么有参数删所有数据
-- DELETE FROM users
-- WHERE userid = 'Bbiri';
-- 4.计算列
-- CREATE TABLE tb1(
-- id INT,
-- a INT,
-- b INT,
-- c INT GENERATED ALWAYS AS (a + b) VIRTUAL
-- );
10. 检查所作的修正
SELECT *FROM users;
11. 清空表my_employees
TRUNCATE my_employees;
15、查询书名达到10个字符的书，不包括里面的空格
SELECT name
FROM books
WHERE CHAR_LENGTH(REPLACE(name,' ','')) > 10
