Oracle Usage Summary

DROP TABLE * * * * purge;/to delete tables free space:
If you do not add purge then it is equivalent to just put it in the Recycle Bin.
Purge RecycleBin; /Empty Recycle Bin

Get current date (without time) select To_char (sysdate, ' yyyy-mm-dd ') as F_fulldate from DUAL

To view the primary key for a table:

Select cu.* from User_cons_columns cu, user_constraints au
where cu.constraint_name = au.constraint_name and Au.constraint_type = ' P ' and au.table_name = ' PRODDTA. F43121 '

Date and Julian calendar conversions:
--julian Convert to date
SELECT to_date (19+substr (Lpad (&b,6,0), 1, 1) | | SUBSTR (Lpad (&b,6,0), 2,5), ' yyyyddd ') DATE1 from DUAL

--julian Convert to date
SELECT SUBSTR (&b+1900000,5,3) -1+to_date (SUBSTR (&b+1900000,1,4) | | 0101 ', ' YYYYMMDD ') DATE1 from DUAL

--date converted to Julian
SELECT To_number (SUBSTR (To_char (' 2013-09-03 ', ' yyyy-mm-dd '), ' ccyyddd '), 2,6)) JULIAN from DUAL

Oracle Usage Summary