如何在 MySQL 中一次对多列进行排序?
若要一次对多列排序,可以使用 ORDER BY 子句。以下是语法 −
select yourColumnName1,yourColumnName2,yourColumnName3 from yourTableName order by yourColumnName2,yourColumnName3;
我们先创建一个表 −
mysql> create table doubleSortDemo -> ( -> StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> StudentName varchar(100), -> StudentCountryName varchar(10) -> ); Query OK, 0 rows affected (0.71 sec)
下面是使用 insert 命令在表中插入记录的查询 −
mysql> insert into doubleSortDemo(StudentName,StudentCountryName) values('John','AUS'); Query OK, 1 row affected (0.21 sec) mysql> insert into doubleSortDemo(StudentName,StudentCountryName) values('Sam','UK'); Query OK, 1 row affected (0.20 sec) mysql> insert into doubleSortDemo(StudentName,StudentCountryName) values('Bob','US'); Query OK, 1 row affected (0.16 sec) mysql> insert into doubleSortDemo(StudentName,StudentCountryName) values('Carol','UK'); Query OK, 1 row affected (0.32 sec) mysql> insert into doubleSortDemo(StudentName,StudentCountryName) values('David','AUS'); Query OK, 1 row affected (0.19 sec) mysql> insert into doubleSortDemo(StudentName,StudentCountryName) values('Larry','UK'); Query OK, 1 row affected (0.15 sec)
下面是使用 select 语句从表中显示所有记录的查询 −
mysql> select * from doubleSortDemo;
这将产生以下输出 −
+-----------+-------------+--------------------+ | StudentId | StudentName | StudentCountryName | +-----------+-------------+--------------------+ | 1 | John | AUS | | 2 | Sam | UK | | 3 | Bob | US | | 4 | Carol | UK | | 5 | David | AUS | | 6 | Larry | UK | +-----------+-------------+--------------------+ 6 rows in set (0.00 sec)
以下是执行 MySQL 排序的查询,涉及到多列,即学生国家和姓名 −
mysql> select StudentId,StudentName,StudentCountryName from doubleSortDemo -> order by StudentCountryName,StudentName;
这将产生以下输出 −
+-----------+-------------+--------------------+ | StudentId | StudentName | StudentCountryName | +-----------+-------------+--------------------+ | 5 | David | AUS | | 1 | John | AUS | | 4 | Carol | UK | | 6 | Larry | UK | | 2 | Sam | UK | | 3 | Bob | US | +-----------+-------------+--------------------+ 6 rows in set (0.00 sec)
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