orale sql 基本操作语句《教程1》

基本语句

查

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