#全外

 use girls;

 SELECT b.*,a.*

 FROM beauty b

 FULL OUTER JOIN boys a

 on b.boyfrien_id=a.id;

 #交叉連線99標準笛卡爾乘積

 SELECT b.*,ob.*

 FROM beauty b

 CROSS JOIN boys ob;

 #sql92和sql99pk

 #功能：sql99支援的較多

 #可讀性：sql99實現連線條件和篩選條件分離，可讀性較高

 #一、查詢編號>3的女神的男朋友資訊，如果有則列出詳細，如果沒有，用nu11填充、

 SELECT b.id,b.name,be.*
 

 FROM beauty b

 LEFT OUTER JOIN boys be

 ON b.boyfriend_id=be.id

 and b.id>3;

 #二、查詢哪個城市沒有部門

 USE myemployees;

 SELECT city

 FROM locations l

 LEFT OUTER JOIN departments d

 on d.location_id=l.location_id

 WHERE d.department_id is null;

 #三、查詢部門名為SAM或IT的員工資訊

 SELECT e.*,d.department_name

 FROM employees e
 

 LEFT OUTER JOIN departments d

 on e.department_id=d.department_id

 WHERE d.department_name in('SAL','IT');