mysql - 避免单个表的嵌套子查询

Answer 1

在“一个查询”中，您可以使用 HAVING 子句：

select sales_id, max(revision)
from Sales
group by sales_id
having max(revision) = 0;

select sales_id, max(revision)
from Sales
group by sales_id
having max(revision) = 1;

我在 SqlFiddle 中添加了您的查询，您可以查看执行计划以了解差异。

SqlFiddle