Oracle学习笔记（五）

组合集总计：
group by with rollup/cube

grouping sets

子查询按执行方式分：标准子查询、关联子查询

标准子查询：嵌套子查询

标量值查询

case with then

使用exits查询

select user_id,user_name from tb_001 tb
 where [not] exists (select 'x'
                 from tb_001
                 where manager_id=tb.user_id )

关联更新
update table1 alias1
set column=(select expression
            from table2 alias2
            where alias1.column=alias2.column);

关联删除
delete from table1 alias11
where column operator
               (select expression
                from table2 alias2
                where alias1.column=alias2.column);

分层结构

分层检索
select [level],column,expr...
from table
[where with condition(s)]
[connect by prior condition(s)]

connect by prior column1=column2

top down:
colum1=parentkey
column2=childkey

bottom up:
column1=childkey
column2=parentkey

插入语句insert statement

insert into table[(column[,column...])]
values(value[,value...])

修改语句update statement

update table
set column=value[,column=value,...]
[where condition];

多表插入语句(Multitable Insert Statements)

insert [all] [conditional_insert_clause]
[insert_into_cause values_clause](subquery)

conditional_insert_clause
[all][first]
[when condition then][insert_into_clause values_clause]
[else][insert_into+clause values_clause]

列：
intsert all
into tb_user values(id,uid,upwd)
into tb_user_info values(id,name,sex,age)
select id,uid,upwd,name,sex,age
from tb_u_10
where id>10000;

待条件的多行插入
insert all
when id>11000 then
into tb_user values(id,uid,upwd)
when age>40 then
into tb_user_info values(id,name,sex,age)
select id,uid,upwd,name,sex,age
from tb_u_10
where id>10000;

insert first
when conditional then
into ...
when conditional then
into ...
else
into...
select...

创建索引
cretate table t_10
(id number(6) not null primary key using index (create index index1 on t_10(id)),
name varchar2(50));

查询索引
select * from user_indexes;