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题解 | 获取employees中的first_name

select first_name from employees order by right(first_name, 2)

2025-08-15

0 28

题解 | 查找字符串中逗号出现的次数

select id, length(string)-length(replace(string, ',', '')) as cnt from strings

2025-08-15

0 43

题解 | 将employees表中的last_name和first_name通过符号连接起来

select concat(last_name, "'", first_name) as name from employees

2025-08-15

0 28

题解 | 删除emp_no重复的记录，只保留最小的id对应的记录。

delete from titles_test where id not in ( select * from ( select min(id) as min_id from titles_test group by emp_no ...

2025-08-15

0 34

题解 | 对first_name创建唯一索引uniq_idx_firstname

ALTER TABLE actor ADD UNIQUE INDEX uniq_idx_firstname (first_name); ALTER TABLE actor ADD INDEX idx_lastname (last_name);

2025-08-15

0 30

题解 | 创建一个actor_name表

create table if not exists actor_name( first_name varchar(45) not null, last_name varchar(45) not null ); insert into actor_name (first_name,...

2025-08-15

0 36

题解 | 批量插入数据，不使用replace操作

INSERT IGNORE INTO actor (actor_id, first_name, last_name, last_update) VALUES ('3', 'ED', 'CHASE', '2006-02-15 12:34:33');

2025-08-15

0 31

题解 | 批量插入数据

insert into actor (actor_id, first_name, last_name, last_update) values(1, 'PENELOPE', 'GUINESS', '2006-02-15 12:34:33'); insert into actor (actor_id,...

2025-08-15

0 22

题解 | 创建一个actor表，包含如下列信息

create table if not exists actor( actor_id smallint(5) not null PRIMARY KEY, first_name varchar(45) not null, last_name varchar(45) not nu...

2025-08-15

0 48

题解 | 将employees表的所有员工的last_name和first_name拼接起来

select concat(last_name, ' ', first_name) as Name from employees

2025-08-15

0 46