将所有to_date为9999-01-01的全部更新为NULL

id	emp_no	title	from_date	to_date
1	10001	Senior Engineer	2001-01-01	NULL
2	10002	Staff	2001-01-01	NULL
3	10003	Senior Engineer	2001-01-01	NULL
4	10004	Senior Engineer	2001-01-01	NULL
5	10001	Senior Engineer	2001-01-01	NULL
6	10002	Staff	2001-01-01	NULL
7	10003	Senior Engineer	2001-01-01	NULL

后台会执行下面SQL语句得到输出，判断正确:

select count(*) from titles_test where from_date='2001-01-01' and to_date is NULL;

示例1

输入:

drop table if exists titles_test;
CREATE TABLE  titles_test (
   id int(11) not null primary key,
   emp_no  int(11) NOT NULL,
   title  varchar(50) NOT NULL,
   from_date  date NOT NULL,
   to_date  date DEFAULT NULL);

insert into titles_test values
('1', '10001', 'Senior Engineer', '1986-06-26', '9999-01-01'),
('2', '10002', 'Staff', '1996-08-03', '9999-01-01'),
('3', '10003', 'Senior Engineer', '1995-12-03', '9999-01-01'),
('4', '10004', 'Senior Engineer', '1995-12-03', '9999-01-01'),
('5', '10001', 'Senior Engineer', '1986-06-26', '9999-01-01'),
('6', '10002', 'Staff', '1996-08-03', '9999-01-01'),
('7', '10003', 'Senior Engineer', '1995-12-03', '9999-01-01');

输出:

原站题解

Sqlite 解法, 执行用时: 10ms, 内存消耗: 3256KB, 提交时间: 2021-12-31

update titles_test
set to_date =null
, from_date ='2001-01-01'
where to_date='9999-01-01'

Sqlite 解法, 执行用时: 10ms, 内存消耗: 3328KB, 提交时间: 2021-08-04

update titles_test set to_date = null , from_date = '2001-01-01' where to_date = '9999-01-01'

Sqlite 解法, 执行用时: 10ms, 内存消耗: 3328KB, 提交时间: 2021-06-15

update titles_test 
set to_date = NULL,from_date = "2001-01-01"
where to_date = "9999-01-01";

Sqlite 解法, 执行用时: 10ms, 内存消耗: 3328KB, 提交时间: 2021-05-28

UPDATE titles_test SET to_date=NULL ,from_date='2001-01-01'
WHERE to_date='9999-01-01';

Sqlite 解法, 执行用时: 10ms, 内存消耗: 3340KB, 提交时间: 2021-07-22

Update titles_test set 
to_date = NULL, from_date='2001-01-01'
where to_date='9999-01-01'

详情