oracle行转列
select i.sid,i.sname,i.birthday,i.schooltime,i.sphone,c.classname,a.assnname,sum(decode(subject,'语文',s.score,0)) as chin,
sum(decode(subject,'数学',s.score,0)) as math,
sum(decode(subject,'英语',s.score,0)) as eng from student_info i
left join student_expand e on i.sid = e.sid left join student_class c on
c.classid = e.classid left join student_assn a on a.assnid = e.assnid left join student_score s on s.sid = i.sid
group by i.sid,i.sname,i.birthday,i.schooltime,i.sphone,c.classname,a.assnname;
行转列:
decode(subject,'数学',s.score,0) 用法:如果subject会等于数学 ,则最后值等于 s.score 否则值等于: 0
相关文档：
1. 将数据库完全导出
用户名system 密码system 导出到Oracle用户目录下的testdb20100522.dmp文件中
#exp system/system@testdb file=testdb20100522.dmp full=y
2. 将数据库中system用户与sys用户的表导出
#exp system/system@testdb file= testdb20100522.d ......
一个使用ibatis对数据库增删改查的例子:
这里用的开发环境是:Eclipse3.2+mysql5.0.20,ibatis包是ibatis-common-2.jar,
ibatis-dao-2.jar,ibatis-sqlmap-2.jar,mysql包是mysql-connector-java-5.0.3-bin.jar.
步骤:
1.创建数据库:
create database itcast;
use itcast;
创建表：
create table stu ......
60.AVG(DISTINCT|ALL)
all表示对所有的值求平均值,distinct只对不同的值求平均值
SQLWKS> create table table3(xm varchar(8),sal number(7,2));
语句已处理。
SQLWKS> insert into table3 values(gao,1111.11);
SQLWKS> insert into table3 values(gao,1111.11);
SQLWKS> insert into table3 values(zhu ......
1. 查看Oracle创建过哪些用户
>select username from all_users;
2. 查看Oracle创建过哪些表空间，表空间的名字和大小
>select t.tablespace_name, round(sum(bytes/(1024*1024)),0) ts_size
from dba_tablespaces t, dba_data_files d
wher ......
CREATE OR REPLACE TYPE ty_str_array IS TABLE OF VARCHAR2 (4000);
CREATE OR REPLACE FUNCTION fn_split (p_str IN VARCHAR2, p_delimiter IN VARCHAR2)
RETURN ty_str_split
IS
j INT := 0;
i INT := 1;
len INT := 0;
&nbs ......
