题目描述

将employees表的所有员工的last_name和first_name拼接起来作为Name，中间以一个空格区分

(注：该数据库系统是sqllite,字符串拼接为 || 符号，不支持concat函数)

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`));

输入描述

无

输出描述

Name
Facello Georgi
Simmel Bezalel
Bamford Parto
Koblick Chirstian
Maliniak Kyoichi
Preusig Anneke
Zielinski Tzvetan
Kalloufi Saniya
Peac Sumant
Piveteau Duangkaew
Sluis Mary

题解

select last_name||" "||first_name as name from employees;

备注：

1. 不同数据库连接字符串的方法不完全相同，MySQL、SQL Server、Oracle等数据库支持CONCAT方法，而本题限定SQLite数据库，只支持用**连接符号”||”**来连接字符串。

2. CONCAT() 方法：

   select CONCAT(CONCAT(last_name," "),first_name) as name  from employees;
   或者
   select CONCAT(last_name," "，first_name) as name  from employees;