declare
tabName varchar(128);
a number;
begin
select table_name into tabName from user_tables where rownum = 1;
dbms_output.put_line(tabName);
if ('aa' = 'Aa') then
a := 5;
else
a := 6;
end if;
dbms_output.put_line(a);
end;
/*
ICOL$
6
*/

-----------------------------------------------------------------

begin
dbms_output.put_line(0.95F); --float
dbms_output.put_line(0.95D); --double
dbms_output.put_line(0.95);
dbms_output.put_line(trunc(25.176, 1));
dbms_output.put_line(trunc(25.176, -1));
dbms_output.put_line(round(25.176, 1));
dbms_output.put_line(round(25.176, -1));
dbms_output.put_line(ceil(25.176));
dbms_output.put_line(floor(25.176));
end;
/*
9.49999988E-001
9.4999999999999996E-001
.95
25.1
20
25.2
30
26
25
*/

-------------------------------------------------------------------

declare
-- tabName varchar(128); -- no need
num number;
begin
for tabName in (select table_name from user_tables) loop
dbms_output.put_line(tabName.table_name);
end loop;
for num in 1 .. 5 loop
dbms_output.put_line(num);
end loop;
end;

----------------------------------------------------------------------

select ascii(' '), initcap('xu weigui'), ltrim('aaaadfdfd', 'a') from dual;

select interval '40' year from dual;

select interval '40-3' year to month from dual;
----------------------------------------------------------------------

declare
a interval year to month;
begin
a := numtoyminterval(10.5, 'year');
dbms_output.put_line(a);
end;

/*
+10-06
*/
----------------------------------------------------
declare
type mytype is table of varchar2(100) index by binary_integer;
mytable mytype;

begin
mytable(1) := 'xuweigui';
mytable(123) := 'Andy';
dbms_output.put_line(mytable(1));
dbms_output.put_line(mytable(123));
end;

--------------------------------------------------------------
declare
type mytype is table of varchar2(100);
mytable mytype := mytype('a');
mytable2 mytype :=mytype(5,4,3,2,1); --Until you initialize it, a nested table or varray is atomically null;

begin
if mytable is null then
null;
elsif mytable.count =0 then
null;
end if;

dbms_output.put_line('mytable init');
for i in mytable.first .. mytable.last loop
dbms_output.put_line(mytable(i));
end loop;

mytable.extend(5);
dbms_output.put_line('mytable.extend(5)');
for i in mytable.first .. mytable.last loop
dbms_output.put_line(mytable(i));
end loop;

mytable(1) := 'xuweigui';
mytable(6) := 'Andy';
dbms_output.put_line('mytable assign value');
for i in mytable.first .. mytable.last loop
dbms_output.put_line(mytable(i));
end loop;

dbms_output.put_line('mytable2 init');
for i in mytable2.first .. mytable2.last loop
dbms_output.put_line(mytable2(i));
end loop;

mytable2.extend(20);
dbms_output.put_line('mytable2 extend(20)');
for i in mytable2.first .. mytable2.last loop
dbms_output.put_line(mytable2(i));
end loop;

exception
when collection_is_null then
dbms_output.put_line('exception');
end;