Oracle dates

operands.sql

//current_date
SELECT TO_CHAR(CURRENT_DATE, 'DD-MON-YYYY HH:MI:SS') FROMDUAL;
SELECT TO_CHAR(SYSDATE, 'DD-MON-YYYY HH:MI:SS') FROM DUAL;

/*
Day: D, DD, DDTH, DAY
Month: MM, MON
Year; YY,YYYY-RR,RRRR
*/

//add days
SELECT SYSDATE + 1 FROM DUAL;
SELECT SYSDATE - 1 FROM DUAL;

//add months
SELECT add_months(TO_DATE('27-JAN-2007'), 1) FROM DUAL;

//greatest
SELECT GREATEST(datecol1, datecol2, datecol3)
FROM t;

//next_day
SELECT NEXT_DAY(SYSDATE, 'FRI') FROM DUAL;

//to_char ¿?
SELECT TO_CHAR(SYSDATE + INTERVAL '10' MINUTE, 'HH:MI:SS')
FROM DUAL;

//Stringn to date conversion
SELECT TO_DATE(string, mask)

masks:
YEAR,YYYY,YY
MM,MONTH,MON
WW,W,
HH, HH12, HH24
MI
SS, 


//select a part of the date
//Trunc (datetime, format)
SELECT TO_CHAR(TRUNC(SYSDATE, 'YEAR'), 'DD-MON-YYYY HH:MI:SS')
FROM DUAL;

comparing
SELECT * FROM t
WHERE TRUNC(datecol) = TRUNC(SYSDATE);