diff --git a/boot-service/src/main/java/com/xwbing/demo/oracle/day02.sql b/boot-service/src/main/java/com/xwbing/demo/oracle/day02.sql
index bf7ecfb..912fd02 100644
--- a/boot-service/src/main/java/com/xwbing/demo/oracle/day02.sql
+++ b/boot-service/src/main/java/com/xwbing/demo/oracle/day02.sql
@@ -154,10 +154,11 @@ NULL与数字运算结果还是NULL
 查看每个员工的收入?
 SELECT ENAME,SAL,COMM FROM EMP_XWBING;
 
-NVL(P1,P1) 若p1为NULL,函数返回p2. 若不为NULL,函数返回p1自身.所以该函数的作用是将NULL替代换为非NULL值
-查看每个员工的收入?
-SELECT ENAME,SAL,SAL+nvl(BOUNS,0) FROM EMP_XWBING;
-SELECT ENAME,SAL,SAL+IFNULL(BOUNS,0) FROM EMP_XWBING;//MYSQL---------
+NVL(P1,P2) 若p1为NULL,函数返回p2. 若不为NULL,函数返回p1自身.所以该函数的作用是将NULL替代换为非NULL值
+查看员工总收入?
+SELECT ENAME,nvl(sum(SAL),0) FROM EMP_XWBING;
+//MYSQL
+SELECT ENAME,IFNULL(sum(SAL),0) FROM EMP_XWBING;//MYSQL---------
 NVL2(P1,P2,P3) 若p1不为NULL值为p2,p1为NULL值为p3
 查看每个员工的奖金情况?
 SELECT ENAME,SAL,NVL2(BOUNS,'有奖金','无奖金') FROM EMP_XWBING;
diff --git a/boot-service/src/main/java/com/xwbing/demo/oracle/day03.sql b/boot-service/src/main/java/com/xwbing/demo/oracle/day03.sql
index df1cb24..9081965 100644
--- a/boot-service/src/main/java/com/xwbing/demo/oracle/day03.sql
+++ b/boot-service/src/main/java/com/xwbing/demo/oracle/day03.sql
@@ -61,11 +61,11 @@ MAX,MIN 统计最大值,最小值
 查看最高工资?
 SELECT MAX(sal),MIN(sal) FROM emp_xwbing;
 
-AVG,SUM 统计平均值与总和
+AVG,SUM 统计平均值与总和,无值为null
 查看平均工资和工资总和
 SELECT trunc(AVG(sal)) avg,SUM(sal) sum FROM emp_xwbing;
 
-COUNT 统计的是记录条数,而不关注具体该字段的取值,
+COUNT 统计的是记录条数,而不关注具体该字段的取值,无值为0
 统计表中记录数,常使用 COUNT(*)
 查看公司员工人数?
 SELECT COUNT (*) FROM emp_xwbing;