MySQL中ORDER BY详解 ORDER BY子句对查询结果排序的方法

按员工薪资说明排序； -
直接按照工资降序排列
这是一个陷阱，不信别做。

asc在mysql中什么意思 升序排列关键字说明

Hey man, the ASC you asked about in MySQL, I've been using it for many years.记得有一次，我帮朋友的公司报数据。
They searched for user information in ascending age, and then displayed the users information in ascending name if they matched. The SQL statement I wrote at the time found that the names of the users sorted by age were incorrect. It happened that I forgot to add commas to separate the sort in multiple columns.嘿，这是一个大陷阱。

还有一次，在这个项目中他们替换了大量的测试成绩。
That is why they wanted to divide them by ascending scores, but no previous values ​​went. I should think of a way to use the ISNULL keyword to set null values ​​to the end.这一次他们心满意足了。

Speaking of best practices, I took on a project with a large amount of data and wanted to digest the order and quantity. I've added a list of tables, but I still find it kind of slow.这是使用 MySQL 文件排序发生的。
I suggested that they reduce the number of fields in the lots, and then add a limit to limit the set of results that should solve the problem.
About common problems, I have experienced many. For example, sometimes the lottery results do not meet expectations, which is probably a problem with the data type conversion or sorting rule. I would like to request that you convert the data to type express or combine the comparison and comparison of characters.
为了解决瓶颈，我使用 EXPLAIN 使用 filesort 来查找它。
Then I need to suggest to add indexes or conditions to optimize the query.
In summary, although the ASC keyword is simple, to use it effectively, it must be adapted for the actual situation.我也遇到了前面旅游专栏的问题。
因为顺序的顺序与列表的顺序不匹配。
Later, I proposed that they adjust the list order or query statements.
Hey, speaking of these experiences, it really gave me a better understanding of database optimization.但归根结底，还是取决于具体的任务，无法生成。

mysql中asc是什么意思

MySQL ASC 用于降序排序；数字和字母都可以接受。
例如，按年龄降序、姓名降序查看员工列表。
注：如果不写ASC，则默认为降序；多列排序是一种列顺序。

mysql中ORDER BY语句的使用

ORDERBY 按字段排序，NULL 最小。

按年龄升序：SELECT FROM Students ORDER BY Age ASC；
按班级升序，分数降序：SELECT FROM Students ORDER BY class_id，分数 DESC；
先过滤后排序：WHERE Age > 1 8 ORDER BY name ASC；
按位置排序（不推荐）：SELECT name、age FROM Students ORDER BY 2 DESC；
NULL 值在前台按升序排列，最后按降序排列。

添加索引以提高性能，对大量数据使用 LIMIT：SELECT FROM Students ORDER BY 分数 DESC LIMIT 1 0;
你自己决定。