想求平均值
我的数据库表里有4个学校的语文成绩和学校的考试人数,求平均值如下:
a=((SelectInfoVO)array1.get(0)).getYuwen_score()*((SelectInfoVO)array1.get(0)).getStu_num()+((SelectInfoVO)array1.get(1)).getYuwen_score()*((SelectInfoVO)array1.get(1)).getStu_num()+((SelectInfoVO)array1.get(2)).getYuwen_score()*((SelectInfoVO)array1.get(2)).getStu_num()+((SelectInfoVO)array1.get(3)).getYuwen_score()*((SelectInfoVO)array1.get(3)).getStu_num()
b=((SelectInfoVO)array1.get(0)).getStu_num+((SelectInfoVO)array1.get(1)).getStu_num
+((SelectInfoVO)array1.get(2)).getStu_num+=((SelectInfoVO)array1.get(3)).getStu_num平均值=a/b4组值比较少,可以象上面那么写,要是有N多组值,应该怎么求???哪为大侠帮我优化一下
我的数据库表里有4个学校的语文成绩和学校的考试人数,求平均值如下:
a=((SelectInfoVO)array1.get(0)).getYuwen_score()*((SelectInfoVO)array1.get(0)).getStu_num()+((SelectInfoVO)array1.get(1)).getYuwen_score()*((SelectInfoVO)array1.get(1)).getStu_num()+((SelectInfoVO)array1.get(2)).getYuwen_score()*((SelectInfoVO)array1.get(2)).getStu_num()+((SelectInfoVO)array1.get(3)).getYuwen_score()*((SelectInfoVO)array1.get(3)).getStu_num()
b=((SelectInfoVO)array1.get(0)).getStu_num+((SelectInfoVO)array1.get(1)).getStu_num
+((SelectInfoVO)array1.get(2)).getStu_num+=((SelectInfoVO)array1.get(3)).getStu_num平均值=a/b4组值比较少,可以象上面那么写,要是有N多组值,应该怎么求???哪为大侠帮我优化一下
非要在外面积算就像楼上说的,用循环
create table TEACH_UPLOAD_T
(
UPLOAD_DATE DATE,
SCHOOL_NAME VARCHAR2(200),
SCHOOL_TYPE VARCHAR2(200),
STU_NUM INTEGER,
EXAM_NAME VARCHAR2(200),
TELPHONE VARCHAR2(15),
YUWEN_SCORE FLOAT,
SHUXUE_SCORE FLOAT,
WAIYU_SCORE FLOAT,
ZHENGZHI_SCORE FLOAT,
LISHI_SCORE FLOAT,
DILI_SCORE FLOAT,
WULI_SCORE FLOAT,
HUAXUE_SCORE FLOAT,
SHENGWU_SCORE FLOAT
)
tablespace WIS_TAB_BASE
pctfree 10
initrans 1
maxtrans 255
storage
(
initial 64K
minextents 1
maxextents unlimited
);
比如oracle直接可以用数据库带的函数求平均值