1.查找表中的元素:select * from table_name
2.dual # 系统一张空表
3.select sysdate from dual # 获取系统的时间
4.select 列名 from table_name where 条件 # 取出满足条件的数据
5.select enname,sal from emp where enname like '%ni%'
6.select lower(enname) from emp # 将enname 都转化为小写
7.select substr(enname,2,3)from emp # 从第二个字符开始截取3个字母
8.select chr(65) from dual # 将65转化为字符
9.select ascii(’A') from dual #将ASCII码转化为字符串
10.select round(23.565) from dual # 四舍五入
11.select round(23.565,2) from dual # 四舍五入到第二位
12.select to_char(sysdate,'YY-MM-DD HH24:MI:SS) from dual # 二十四小时显示
13.select enname from emp where sal = (select max(sal) from emp); # 查找部门薪资最高的人。
增
1. insert into class values(1000,'c1')
2. insert into stu(id,name,class,email) values(1,'a',1000,'a');
3.
oracle 增删改查实例
筛选整点时间
SELECT
f_time,tem_value
FROM
tem_chejian
WHERE
f_time
LIKE
'%:00:00';
改 AIM_HUM 填充,AIM_TEM 填充
update input_data t set t.AIM_TEM = (SELECT
c.tem_value
FROM
tem_chejian c
WHERE
c.f_time LIKE '%:00:00' and t.CURRENT_TIME = c.f_time)
update input_data t set t.AIM_HUM = (SELECT
d.HUm_value
FROM
hum_chejian d
WHERE
d.f_time LIKE '%:00:00' and t.CURRENT_TIME = d.f_time);
查询 AIM_HUM,AIM_TEM
SELECT
*
FROM
input_data t,tem_chejian c
WHERE
t.CURRENT_TIME = c.f_time;
改
UPDATE input_data t set MACHINE_IS_WORK = "1"
FROM
BATCH_INFO b
WHERE
b.F_BEGIN_TIME < t.CURRENT_TIME AND t.CURRENT_TIME < b.F_END_TIME