--Zad 4
select power((log(5,123)+log(10,sqrt(1234)))/(power(1234,1/3)+12),3) from dual;

--Zad 8
select systimestamp-interval '567 8:09' day(3) to minute,
sysdate + interval '129-11'year(3) to month,
to_char(sysdate + interval '129-11'year(3) to month,'dd.mm.yyyy cc ddd d day w ww q'), 
trunc(sysdate,'yy') , TIMESTAMP '2004-11-14 21:00:06.5'
from dual;

--Zad 11
select * from studenci where to_char (data_urodzenia,'dd-mm')=to_char(sysdate,'dd-mm') ;

--Zad 15
select count (*) , avg(placa),round(avg(months_between(sysdate,data_zatr)),1) from pracownicy
where data_zatr<=sysdate and (data_zwol is NULL or data_zwol>=sysdate) and
data_zatr between to_date ('01.01.2010','dd.mm.yyyy') and
to_date ('01.01.2010','dd.mm.yyyy')+interval '10' year ;

--Zad 25
select * from studenci where regexp_count(imiona ,'[[:alpha:]]') = 5 and
regexp_like(upper(nazwisko),'^(KO|JAN)[[:alpha:]]{0,}\s?(SKI)$');