In Oracle, the ROUND(date) function returns a date rounded to a specified date unit.
By default, it rounds the date to the nearest day, but you can provide an optional argument that specifies an alternative unit to use.
Oracle also has a ROUND(number) syntax, which is used on number. This article is solely about the ROUND(date) syntax, which is used on date.
In Oracle Database, the COLLATION() function returns the name of the derived collation for its argument.
In Oracle Database, the NLS_CHARSET_NAME() function returns the character set name of a given character set, based on its ID. You pass the character set ID as an argument, and the function returns its name.
In Oracle Database, the NLS_COLLATION_NAME() function returns the name of a given collation, based on its ID. You pass the collation ID when calling the function, and it returns the collation name.
In Oracle Database, the NLS_COLLATION_ID() function returns the ID of a given collation. You pass the collation name when calling the function, and it returns the collation ID.
In Oracle, the NLS_CHARSET_DECL_LEN() function returns the declaration length (in number of characters) of an NCHAR column.
In Oracle, the NLS_CHARSET_ID() function returns the character set ID number of a given character set. You pass the character set name as an argument, and it returns its ID.
In Oracle Database, the FROM_TZ() function converts a timestamp value and a time zone to a TIMESTAMP WITH TIME ZONE value.
You pass the timestamp value and the time zone as two separate arguments, and the function returns them as a TIMESTAMP WITH TIME ZONE value.
Sometimes we need to specify a time zone when using datetime functions in Oracle.
But there are a lot of time zones out there. How do we remember them all? And how do we know our system supports a given time zone?
Fortunately, we can query the V$TIMEZONE_NAMES view to return a list of valid time zones.
In Oracle Database, the SESSIONTIMEZONE function returns the time zone of the current session.