下面的操作将更新一个表中的所有行

Update Table Set
Column1 = 'New Value'

下一个将更新Column2值大于5的所有行

Update Table Set
Column1 = 'New Value'
Where
Column2 > 5

Unkwntech有一个更新多个表的例子

UPDATE table1, table2 SET
table1.col1 = 'value',
table2.col1 = 'value'
WHERE
table1.col3 = '567'
AND table2.col6='567'

这个问题很老了，但我想用另一个答案来扩展这个话题。

我的观点是，实现它的最简单的方法是用一个事务包装多个查询。这句话的意思是:ON DUPLICATE KEY UPDATE是一个很好的黑客，但人们应该意识到它的缺点和限制:

As being said, if you happen to launch the query with rows whose primary keys don't exist in the table, the query inserts new "half-baked" records. Probably it's not what you want If you have a table with a not null field without default value and don't want to touch this field in the query, you'll get "Field 'fieldname' doesn't have a default value" MySQL warning even if you don't insert a single row at all. It will get you into trouble, if you decide to be strict and turn mysql warnings into runtime exceptions in your app.

I made some performance tests for three of suggested variants, including the INSERT ... ON DUPLICATE KEY UPDATE variant, a variant with "case / when / then" clause and a naive approach with transaction. You may get the python code and results here. The overall conclusion is that the variant with case statement turns out to be twice as fast as two other variants, but it's quite hard to write correct and injection-safe code for it, so I personally stick to the simplest approach: using transactions.

编辑:Dakusan的发现证明我的性能估计不太有效。请参阅另一个更详细的研究的答案。

我从@newtover中得到答案，并使用MySql 8中的新json_table函数扩展它。这允许你创建一个存储过程来处理工作负载，而不是在代码中构建自己的SQL文本:

drop table if exists `test`;
create table `test` (
  `Id` int,
  `Number` int,
  PRIMARY KEY (`Id`)
);
insert into test (Id, Number) values (1, 1), (2, 2);

DROP procedure IF EXISTS `Test`;
DELIMITER $$
CREATE PROCEDURE `Test`(
    p_json json
)
BEGIN
    update test s
        join json_table(p_json, '$[*]' columns(`id` int path '$.id', `number` int path '$.number')) v 
        on s.Id=v.id set s.Number=v.number;
END$$
DELIMITER ;

call `Test`('[{"id": 1, "number": 10}, {"id": 2, "number": 20}]');
select * from test;

drop table if exists `test`;

它比纯SQL慢了几毫秒，但我很高兴接受打击，而不是在代码中生成SQL文本。不确定它对巨大记录集的性能如何(JSON对象的最大大小为1Gb)，但我在一次更新10k行时一直使用它。

由于您有动态值，因此需要为要更新的列使用IF或CASE。虽然有点难看，但应该能行。

用你的例子，你可以这样做:

UPDATE table SET Col1 = CASE id 
                          WHEN 1 THEN 1 
                          WHEN 2 THEN 2 
                          WHEN 4 THEN 10 
                          ELSE Col1 
                        END, 
                 Col2 = CASE id 
                          WHEN 3 THEN 3 
                          WHEN 4 THEN 12 
                          ELSE Col2 
                        END
             WHERE id IN (1, 2, 3, 4);

下面是简单的方法

update my_table m, -- let create a temp table with populated values
    (select 1 as id, 20 as value union -- this part will be generated
     select 2 as id, 30 as value union -- using a backend code
     -- for loop 
     select N as id, X as value
        ) t
set m.value = t.value where t.id=m.id -- now update by join - quick

UPDATE table1, table2 SET table1.col1='value', table2.col1='value' WHERE table1.col3='567' AND table2.col6='567'

这应该对你有用。

MySQL手册中有关于多个表的参考。