oracle常用sql整理

select sys_guid() from dual

select dbms_random.value(1000,9999)

select substr('abcdefg',0,5) from dual  --abcde
select substr('abcdefg',1,5) from dual  --abcde
select substr('abcdefg',2,5) from dual  --bcdef

insert into tableA(aaa,bbb,ccc) select sys_guid(),b.xx,'NA' from tableB b