題目描述
將employees表的所有員工的last_name和first_name拼接起來作爲Name,中間以一個空格區分
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`));
解析:
對於字符串拼接,不同數據庫有不同實現方式。Mysql有函數concat(s1,s2...sn)可用,SQLite數據庫用連接符號"||"來連接字符串。
Mysql:
SELECT
concat(first_name, ' ', last_name) AS NAME
FROM
employees;
Sqlite:
SELECT
last_name || ' ' || first_name AS NAME
FROM
employees;