#一、查詢沒有獎金,且工資小於18000 salary,last_name 並排序。
SELECT salary,last_name
FROM employees
WHERE commission_pct IS NULL
AND salary<18000
ORDER BY salary DESC;
#二、查詢employess表中,job_id不爲‘IT’,或者工資爲12000的員工信息
#WHERE job_id <>IT
SELECT *
FROM employees
WHERE job_id NOT IN ('IT')
OR salary=12000;
/*三、經典面試題
試問:SELECT * FROM empoyees; 和
SELRCT * FROM empoyees
WHERE commission_pct
LIKE ‘%%’
AND last_name LIKE ’%%‘;
結果是否一樣?並說明理由。
不一樣
如果判斷的字段有null值
and 換成 or就行了
*/