In Oracle Database, the USER function returns the name of the session user (the user who logged on).
4 Ways to Separate Hours, Minutes, and Seconds from a Time Value in MariaDB
MariaDB has several functions that enable you to extract various date and time parts from date/time values. You can use these to separate each date/time component into its own column if required.
Below are four ways to extract the hours, minutes, and seconds from a time value in MariaDB. As a bonus, we’ll also include microseconds.
SYS_GUID() Function in Oracle
In Oracle Database, the SYS_GUID() function generates and returns a globally unique identifier (RAW value) made up of 16 bytes.
On most platforms, the generated identifier consists of a host identifier, a process or thread identifier of the process or thread invoking the function, and a nonrepeating value (sequence of bytes) for that process or thread.
How to Return Fractional Seconds from a Datetime Value in Oracle
When using Oracle Database, you can use the TO_CHAR(datetime) function to return various parts of a datetime value, including the fractional seconds.
To return the fractional seconds part from a datetime value, use the FF format element.
NULLIF() Function in Oracle
In Oracle Database, the NULLIF() function compares two expressions, and returns null if both expressions are equal. If they are not equal, then the function returns the first expression.
NVL() Function in Oracle
In Oracle Database, the NVL() function allows us to replace null values with another value.
MariaDB Composite Date & Time Units Explained
MariaDB includes a bunch of date and time units that you can use when working with date and time values. For example, MONTH is a unit, and HOUR is another unit.
Some units are composite units. Composite units are when two units get combined into one. The naming convention is that each unit name is separated by an underscore. For example, MINUTE_SECOND is for minutes and seconds.
Below are some examples that demonstrate how composite units work in MariaDB.
COALESCE() Function in Oracle
In Oracle Database, the COALESCE() function returns the first non-null expression the expression list.
How to Add the AD/BC Indicator to a Date in Oracle
When using the TO_CHAR() function to format a datetime value in Oracle Database, you can add the AD/BC indicator by simply adding either AD or BC to your format model.
Oracle then displays the appropriate indicator, depending on whether the date value is AD or BC.
You can provide it in any uppercase or lowercase, and with or without dots (e.g. AD, A.D. ad, a.d, etc). Oracle will then display the indicator as specified.