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题解 | length 返回字符串字符长度

SELECT id,length(string)-length(replace(string,',','')) cnt FROM strings

SQL错题

2023-11-22

0 229

题解 | #将所有获取奖金的员工当前的薪水增加10%#

UPDATE salaries SET salary = salary * 1.1 WHERE to_date = '9999-01-01' AND emp_no IN (SELECT emp_no FROM emp_bonus);

SQL错题

2023-11-21

0 227

题解 | 创建外键约束

ALTER TABLE audit ADD CONSTRAINT fk_emp_no FOREIGN KEY (EMP_no) REFERENCES employees_test(ID);

SQL错题

2023-11-21

1 256

题解 | rename

rename table titles_test to titles_2017

SQL错题

2023-11-20

0 217

题解 | replace

replace into titles_test(id,emp_no,title,from_date,to_date) values ('5', '10005', 'Senior Engineer', '1986-06-26', '9999-01-01')

SQL错题

2023-11-20

2 268

题解 | 显然GPT写的更完美

/* update titles_test set to_date=NULL,from_date='2001-01-01' where to_date='9999-01-01'; */ -- 自己写的 UPDATE titles_test SET to_date = CASE WHEN ...

SQL错题

2023-11-20

1 272

题解 | 越到后面越是这种题越不会

delete t1 from titles_test t1 inner join titles_test t2 where t1.emp_no=t2.emp_no and t1.id>t2.id; select * from titles_test;

SQL错题

2023-11-19

1 252

题解 | #构造一个触发器audit_log#

create trigger audit_log after insert on employees_test for each row begin insert into audit (EMP_no,NAME) VALUES (NEW.ID,NEW.NAME); END

SQL错题

2023-11-19

1 286

题解 |

ALTER TABLE actor ADD COLUMN create_date datetime NOT NULL DEFAULT '2020-10-01 00:00:00' AFTER last_update;

SQL错题

2023-11-19

0 325

题解 | 索引这一块需要加强

select * from salaries force index (idx_emp_no) where emp_no=10005

SQL错题

2023-11-18

2 314