如何查找 MySQL 列的第 n 个最高值?
mysqlmysqli database
要查找列的第 n 个最高值，您需要使用带有 LIMIT 子句的 ORDER BY DESC。如果您想要列的第二高值，请使用以下语法:
SELECT *FROM yourTableName ORDER BY DESC yourColumnName LIMIT 1,1;
如果您想要列的第四高值，请使用以下语法:
SELECT *FROM yourTableName ORDER BY DESC yourColumnName LIMIT 3,1;
如果您想要列的第一高值，请使用以下语法:
SELECT *FROM yourTableName ORDER BY DESC yourColumnName LIMIT 1;
如上语法所述，您只需在 LIMIT 子句中更改。为了理解上述语法，让我们创建一个表。创建表的查询如下:
mysql> create table NthSalaryDemo -> ( -> Id int NOT NULL AUTO_INCREMENT, -> Name varchar(10), -> Salary int, -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (1.03 sec)
使用 insert 命令在表中插入一些记录。 查询语句如下:
mysql> insert into NthSalaryDemo(Name,Salary) values('Larry',5700);
Query OK, 1 row affected (0.41 sec)
mysql> insert into NthSalaryDemo(Name,Salary) values('Sam',6000);
Query OK, 1 row affected (0.16 sec)
mysql> insert into NthSalaryDemo(Name,Salary) values('Mike',5800);
Query OK, 1 row affected (0.16 sec)
mysql> insert into NthSalaryDemo(Name,Salary) values('Carol',4500);
Query OK, 1 row affected (0.17 sec)
mysql> insert into NthSalaryDemo(Name,Salary) values('Bob',4900);
Query OK, 1 row affected (0.20 sec)
mysql> insert into NthSalaryDemo(Name,Salary) values('David',5400);
Query OK, 1 row affected (0.27 sec)
mysql> insert into NthSalaryDemo(Name,Salary) values('Maxwell',5300);
Query OK, 1 row affected (0.21 sec)
mysql> insert into NthSalaryDemo(Name,Salary) values('James',4000);
Query OK, 1 row affected (0.19 sec)
mysql> insert into NthSalaryDemo(Name,Salary) values('Robert',4600);
Query OK, 1 row affected (0.19 sec)
使用 select 语句显示表中的所有记录。查询如下:
mysql> select *from NthSalaryDemo;
输出结果如下:
+----+---------+--------+ | Id | Name | Salary | +----+---------+--------+ | 1 | Larry | 5700 | | 2 | Sam | 6000 | | 3 | Mike | 5800 | | 4 | Carol | 4500 | | 5 | Bob | 4900 | | 6 | David | 5400 | | 7 | Maxwell | 5300 | | 8 | James | 4000 | | 9 | Robert | 4600 | +----+---------+--------+ 9 rows in set (0.00 sec)
案例 1:以下查询用于获取列中第 n 个最高值。
以下查询将给出"Salary"列中第四个最高值:
mysql> select *from NthSalaryDemo order by Salary desc limit 3,1;
输出结果如下:
+----+-------+--------+ | Id | Name | Salary | +----+-------+--------+ | 6 | David | 5400 | +----+-------+--------+ 1 row in set (0.00 sec)
案例 2:以下查询用于获取"Salary"列的第二高值:
mysql> select *from NthSalaryDemo order by Salary desc limit 1,1;
输出结果如下:
+----+------+--------+ | Id | Name | Salary | +----+------+--------+ | 3 | Mike | 5800 | +----+------+--------+ 1 row in set (0.00 sec)
案例 3:这是获取列中第一个最高值的查询:
mysql> select *from NthSalaryDemo order by Salary desc limit 1;
输出结果如下:
+----+------+--------+ | Id | Name | Salary | +----+------+--------+ | 2 | Sam | 6000 | +----+------+--------+ 1 row in set (0.00 sec)
案例 4:如果您想要获取"Salary"列中第 8 高的值，请使用以下查询:
mysql> select *from NthSalaryDemo order by Salary desc limit 7,1;
输出结果如下:
+----+-------+--------+ | Id | Name | Salary | +----+-------+--------+ | 4 | Carol | 4500 | +----+-------+--------+ 1 row in set (0.00 sec)
