diff --git "a/20 \351\203\221\345\274\230\346\231\226/20230322 \344\275\234\344\270\232.md" "b/20 \351\203\221\345\274\230\346\231\226/20230322 \344\275\234\344\270\232.md"
index 9f5fc9b9097b3d1193e7472107a5688a77af0c0a..0263e77eb7b580630f6c89b28a5942b525a03748 100644
--- "a/20 \351\203\221\345\274\230\346\231\226/20230322 \344\275\234\344\270\232.md"	
+++ "b/20 \351\203\221\345\274\230\346\231\226/20230322 \344\275\234\344\270\232.md"	
@@ -51,6 +51,7 @@ select b.id,a.price from price a join fruit b on a.id=b.price_id where name='苹
 
 -- 3.3左外连接
 -- 练习：查询所有水果信息和对应价格信息
+select * from fruit a left join price b on a.price_id=b.id;
 -- fruit f  位于left左边，称为左表，左外连接以左表为主
 -- price p  位于left右边，称为右表
 -- f.* :获取fruit水果表中的所有数据
@@ -64,6 +65,8 @@ select a.`name`,price from fruit a left join price b on a.price_id=b.id where pr
 
 -- 3.4右外连接
 -- 练习：使用右外连接查询所有价格对应的水果名称和价格信息，
+select * from fruit a right join price b on a.price_id=b.id; 
+
 --  right join  表示右连接
 --  price p 称为右表 右外连接会查询右表即price表的全部数据以及和左表fruit f的交集
 
@@ -366,16 +369,15 @@ select b.id,b.ename,b.salary,a.jname,a.description,c.dname,c.loc from job a inne
 	-- 2.确定连接查询的条件 :emp.job_id = job.id and emp.dept_id=dept.id
 	-- 其他条件：e.salary between salarygrade.losalary and salarygrade.hisalary
 	-- 3.确定要查询的结果字段
-	SELECT b.id,b.ename,b.salary,a.jname,a.description,c.dname,c.loc,salarygrade.grade from
-	(select * from 
-	job a 
-	inner join 
-	emp_b b on a.id=b.job_id 
-	inner join 
-	dept_b c on b.d_id=c.id)
-	UNION
-	(select * from salarygrade)
-	where salarygrade.grade in (select * from emp_b where (salary+bonus) between salarygrade.losalary and salarygrade.hisalary);
+select emp_b.ename,emp_b.salary,job.jname,job.description,dept_b.dname,dept_b.loc,salarygrade.grade 
+from 
+emp_b,job,dept_b,salarygrade 
+where emp_b.job_id=job.id 
+and emp_b.d_id=dept_b.id 
+and emp_b.salary 
+between salarygrade.losalary 
+and salarygrade.hisalary;
+