Question

您好我们的系统中丢失了一个acc，我们需要进行检索。幸运的是我们有数据库的备份。现在我试图将备份mysql数据库中的记录添加到当前。但我有一个问题。当我尝试插入数据时，我得到错误＆＃34; ID重复＆＃34;。这是我从备份导出表时得到的。

    INSERT INTO `anketu_perziuros_mine` (`id`, `anketa`, `kada`, `timemark`) VALUES
(955009, 498044, 1443021887, '2015-09-23 18:24:47'),
(147188, 498044, 1443018663, '2015-09-23 17:31:03'),
(948120, 498044, 1443017899, '2015-09-23 17:18:19'),
(958152, 498044, 1442954185, '2015-09-22 23:36:25'),
(888916, 498044, 1442863283, '2015-09-21 22:21:23'),
(782244, 498044, 1442839575, '2015-09-21 15:46:15'),
(827707, 498044, 1442746875, '2015-09-20 14:01:15'),
(869393, 498044, 1442683453, '2015-09-19 20:24:13');

我是mysql的新手。我尝试了许多方法（来自教程）我失败了。如何实现IF NOT EXISTS，还是有其他解决方案？

Answer 1

以下是如何实现恢复丢失数据的说明。请参阅Demo on SQL Fiddle。

-- suppose you have a table 
create table test (
  id int not null primary key,
  val int not null
);

-- with these data
insert into test values
(1,1),
(2,2),
(3,4),
(4,90);

-- lets assume you lost these data from the test table
delete from test where id in (1,4);

-- now you want to restore the lost data from your backup
-- do the following.

-- create a temporal table with schema of test table
create table test2 as 
select * from test limit 0;

-- insert backup data into the temporal table
insert into test2 values
(1,1),
(2,2),
(3,4),
(4,90);

-- copy backup data from temporal table into the real table
insert into test
select * from test2 b
where not exists (select null from test a where a.id=b.id);

-- drop backup data
drop table test2;

将不存在的记录插入Mysql表中

1 个答案: