技術標籤：sql練習mysql

01 基本SQL-SELECT語句

學習了SQL語句後的課後作業

-- 1、顯示錶 departments 的結構，並查詢其中的全部資料
SELECT *
FROM departments;

-- 2、顯示出表 employees 中的全部 job_id（不能重複）
SELECT DISTINCT job_id
FROM employees;

-- 3、顯示出表 employees 的全部列，各個列之間用逗號連線，列頭顯示成 OUT_PUT
SELECT * 
FROM employees;
SELECT CONCAT(employee_id,","
 
,first_name,",",last_name,",",email,",
",phone_number,",",job_id,",",salary,",",IFNULL(commission_pct,0),",",
IFNULL(manager_id,0),",",department_id,",",hiredate) out_put FROM employees;