本文章为尚硅谷教学视频总结，仅供学习及参考。如有侵权请及时告知。

1、SQL执行顺序

（1）手写sql顺序

（2）机读sql顺序

2、7种Join的sql编写

注：图中 full outer join在MySQL中是不支持的。可通过

(1)全有

SELECT 
     
       FROM TableA A LEFT JOIN TableB B ON A.Key = B.Key UNIONSELECT  
      
        FROM TableA A RIGHT JOIN TableB B ON A.Key = B.Key
      
     

（2）A的独有和B的独有

SELECT 
     
       FROM TableA A LEFT JOIN TableB B ON A.Key = B.Key WHERE B.Key IS NULL UNIONSELECT 
      
        FROM TableA A RIGHT JOIN TableB B ON A.Key = B.Key WHERE A.Key IS NULL