【奇数排名】

对于employees表中，输出first_name排名(按first_name升序排序)为奇数的first_name

CREATE TABLE `employees` (
`emp_no` int(11) NOT NULL,
`birth_date` date NOT NULL,
`first_name` varchar(14) NOT NULL,
`last_name` varchar(16) NOT NULL,
`gender` char(1) NOT NULL,
`hire_date` date NOT NULL,
PRIMARY KEY (`emp_no`));

如，输入为：

INSERT INTO employees VALUES(10001,'1953-09-02','Georgi','Facello','M','1986-06-26');
INSERT INTO employees VALUES(10002,'1964-06-02','Bezalel','Simmel','F','1985-11-21');
INSERT INTO employees VALUES(10005,'1955-01-21','Kyoichi','Maliniak','M','1989-09-12');
INSERT INTO employees VALUES(10006,'1953-04-20','Anneke','Preusig','F','1989-06-02');

我的思路：

set @rank = 0;
select first_name,@rank:=@rank+1 as rank
from employees
order by first_name

语雀内容
奇数用%取余
where @rank %2 =1
但是报错

套一层再筛选

set @rank = 0;
select first_name
from
(
select first_name,@rank:=@rank+1 as rank
from employees
order by first_name 
)as r
where rank %2 =1
order by first_name desc

ac过不去 抄个答案

SELECT e1.first_name FROM 
  (SELECT e2.first_name, 
    (SELECT COUNT(*) FROM employees AS e3 
     WHERE e3.first_name <= e2.first_name) 
   AS rowid FROM employees AS e2) AS e1
WHERE e1.rowid % 2 = 1