oracle基本语法

-- 表
create table test (names varchar2(12),
                   dates date,
                   num   int,
                   dou   double);
-- 视图
create or replace view vi_test as
select * from test;

-- 同义词
create or replace synonym aa
for dbusrcard001.aa;

-- 存储过程
create or replace produce dd(v_id in employee.empoy_id%type)
as
begin
   
end
dd;

-- 函数
create or replace function ee(v_id in employee%rowtype) return varchar(15)
is
var_test varchar2(15);
begin
  return var_test;
exception when others then
   
end

-- 三种触发器的定义
create or replace trigger ff
alter delete
on test
for each row
declare
begin
   delete from test;
   if sql%rowcount < 0 or sql%rowcount is null then
      rais_replaction_err(-20004,"错误")
   end if
end


create or replace trigger gg
alter insert
on test
for each row
declare
begin
   if :old.names = :new.names then
      raise_replaction_err(-2003,"编码重复");
   end if
end


create or replace trigger hh
for update
on test
for each row
declare
begin
  if updating then
     if :old.names <> :new.names then
 reaise_replaction_err(-2002,"关键字不能修改")
     end if
  end if
end 

-- 定义游标
declare
   cursor aa is
      select names,num from test;
begin
   for bb in aa
   loop
        if bb.names = "ORACLE" then
        
        end if
   end loop;
   
end

-- 速度优化，前一语句不后一语句的速度快几十倍
select names,dates 
from test,b
where test.names = b.names(+) 
 and b.names is null 
 and b.dates > date(''2003-01-01'',''yyyy-mm-dd'')

 
select names,dates
from test 
where names not in ( select names  from b
                      where dates > to_date(''2003-01-01'',''yyyy-mm-dd''))
                       

-- 查找重复记录
select names,num 
from test 
where rowid != (select max(rowid) 
                 from test b 
                where b.names = test.names and
                      b.num = test.num)


-- 查找表TEST中时间最新的前10条记录
select * from (select * from test order by dates desc) where rownum < 11

-- 序列号的产生
create sequence row_id
minvalue 1
maxvalue 9999999999999999999999
start with 1
increment by 1

insert into test values(row_id.nextval,....)