Oracle SQL

WITH 
T1 as (SELECT field_list FROM T list join WHERE cond group by ...) , 
T2 as (SELECT field_list FROM T list join WHERE cond2 group by ..) , tn as ....
SELECT * FROM T1, T2 where t1.cond= t2.cond

WITH T AS (SELECT * FROM ALL_OBJECTS) , T2 AS 
(SELECT * FROM ALL_tables A , T WHERE T.OBJECT_NAME = A.TABLE_NAME ) 
SELECT TABLE_NAME FROM T2 
 
-- сложное обращение 

WITH T AS (SELECT * FROM ALL_OBJECTS) , 
T2 AS (SELECT * FROM ALL_tables) 
SELECT * FROM T, T2 WHERE T.OBJECT_NAME = T2.TABLE_NAME;
 
-- последовательно используем t1,t2

with 
t1 as (select object_type, created lstcrdt  , object_name from all_objects),
t2 as (select object_type, count(object_name) cnttype from t1 group by object_type)
select * from t1 inner join t2 on t1.object_type = t2.object_type

create table info_user_v (
  id number primary key -- иднтификатор уникальный
, name varchar2(50) -- наименование 
, json_data varchar2(4000) -- данные JSON 
);

alter table info_user_v add constraint c_1_json_data check(json_data is json);

CREATE TABLE prices
( 
 ticker VARCHAR2(3), -- валюта сокращ
 pdate DATE, -- дата 
 price FLOAT -- курс валюты
);

   select count(1) dwcount,
          to_char(to_date('01/01/1940', 'DD/MM/YYYY') + level - 1, 'DAY') daywe -- 1940 это год , который нам нужен
     from dual
   connect by level <
              to_number(to_char(Trunc(To_Date(1940 + 1, 'YYYY'), 'YYYY') - 1, -- 1940 это год , который нам нужен
                                'ddd')) -- считаем колч дней 
    group by to_char(to_date('01/01/1940', 'DD/MM/YYYY') + level - 1, 'DAY'); -- группируем запрос по дням

  with t as (select to_date('31/12/'||'1940','dd/mm/yyyy') fd_year from dual)
    select to_char(t.fd_year-level+1,'DAY') fv_day,count(1) fn_count from t
    connect by level <= to_number(to_char(t.fd_year,'ddd'))
  group by to_char(t.fd_year-level+1,'DAY')

create table tsp(n number primary key); 
-- заполним таблицу данными
insert into tsp
select level from dual connect by level < 100001;

create table ts(n number primary key, m number, CONSTRAINT fk_ts
    FOREIGN KEY (m)
    REFERENCES tsp(n));

insert into ts(n,m)
select level,mod(level,90000)+1 from dual connect by level < 1000000;

delete tsp where n > 99000

UPDATE имя таблицы
  SET обновляемые поля и значения
  WHERE CURRENT OF имя курсора;

create table tab11 as select * from all_objects where rownum < 25;

declare 
    cursor C is
    select *
      from tab11 t
     FOR UPDATE OF object_name, owner; 
begin
  FOR i in C loop
   update tab11 set object_name = 'update1' , owner = 'OW'  
   where current of C;
  end loop; 
  commit;  
end;

 create table s_obj as select * from all_objects where rownum < 5

begin
  for i in (select * from all_objects where rownum < 21) loop 
    i.object_name := 'prefix'||i.owner; --меняем данные перед вставкой
    insert into s_obj values i;
  end loop; 
end;

select * from s_obj
SYS	ICOL$ ...
SYS	I_USER1 ...
...
SYS	prefixSYS ...
SYS	prefixSYS ...
...

select object_name from all_objects where object_type = 'CLUSTER'

 create table copy1 as select * from 
 (select level lnl from dual connect by level < 11) 
cross join (select object_name from all_objects where object_type = 'CLUSTER') 

 select count(*) from copy1

delete from copy1;

insert into copy1(lnl, object_name) 
select * from (select level lnl from dual connect by level < 11) cross join 
(select object_name from all_objects where object_type = 'CLUSTER')

select object_name,count(1) from copy1 group by object_name

create table ttmstamp(t1 timestamp, t2 timestamp with time zone, t3 timestamp with local time zone);

ALTER SESSION SET TIME_ZONE = '-3:0';

select CURRENT_TIMESTAMP from dual;


ALTER SESSION SET TIME_ZONE = '-4:0';
select CURRENT_TIMESTAMP from dual;