有没有办法将两个更新查询合并成一个？

Question

我有多个更新查询。我想在一个声明中这样做。该查询是

update user set name = 'Something' where id = '1'; 
update user set name = 'Newthing' where id = '2'; 

我想是这样

update user set name = 'Something' where id = '1' && update user set name = 'Newthing' where id = '2'; 

Answer 1

当然，仅仅使用一个CASE声明：

update user 
set name = 
    case when id = '1' then 'Something' 
     when id = '2' then 'Newthing' 
    end 
where id in ('1','2') 

Answer 2

为补充sgeddes解决方案：

update user u 
join (select 1 as id,'Something' as name 
     union 
     select 2, 'Newthing') as t 
    on u.id = t.id 
     set u.name = t.name; 

请注意，这将o只能为MySQL工作。其他DBMS，例如Oracle，DB2，MSQL等实现MERGE这是一个标准建设：

merge into user u 
using (
    values (1,'Something') 
     , (2,'Newthing') 
) t (id, name) 
    on t.id = u.id 
when matched then 
    update set u.name = t.name 

通过增加一个条款，你还可以插入

when not matched then 
    insert (id, name) values (t.id, t.name) 

而且合并也可以删除行