Syntax
------ 
NOW([precision])
CURRENT_TIMESTAMP
CURRENT_TIMESTAMP([precision])
LOCALTIME, LOCALTIME([precision])
LOCALTIMESTAMP
LOCALTIMESTAMP([precision])
 
Description
----------- 
Returns the current date and time as a value in 'YYYY-MM-DD
HH:MM:SS'
or YYYYMMDDHHMMSS.uuuuuu format, depending on whether the
function is
used in a string or numeric context. The value is expressed
in the
current time zone.
 
The optional precision determines the microsecond precision.
See Microseconds in MariaDB.
 
NOW() (or its synonyms) can be used as the default value for
TIMESTAMP columns as well as, since MariaDB 10.0.1, DATETIME
columns. Before MariaDB 10.0.1, it was only possible for a
single TIMESTAMP column per table to contain the
CURRENT_TIMESTAMP as its default.
 
When displayed in the INFORMATION_SCHEMA.COLUMNS table, a
default CURRENT TIMESTAMP is displayed as CURRENT_TIMESTAMP
up until MariaDB 10.2.2, and as current_timestamp() from
MariaDB 10.2.3, due to to MariaDB 10.2 accepting expressions
in the DEFAULT clause.
 
Examples
-------- 
SELECT NOW();
+---------------------+
| NOW() |
+---------------------+
| 2010-03-27 13:13:25 |
+---------------------+
 
SELECT NOW() + 0;
 
+-----------------------+
| NOW() + 0 |
+-----------------------+
| 20100327131329.000000 |
+-----------------------+
 
With precision:
 
SELECT CURRENT_TIMESTAMP(2);
+------------------------+
| CURRENT_TIMESTAMP(2) |
+------------------------+
| 2018-07-10 09:47:26.24 |
+------------------------+
 
Used as a default TIMESTAMP:
 
CREATE TABLE t (createdTS TIMESTAMP NOT NULL DEFAULT
CURRENT_TIMESTAMP);
 
From MariaDB 10.2.2:
 
SELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE
TABLE_SCHEMA='test'
 AND COLUMN_NAME LIKE '%ts%'\G
*************************** 1. row
***************************
 TABLE_CATALOG: def
 TABLE_SCHEMA: test
 TABLE_NAME: t
 COLUMN_NAME: ts
 ORDINAL_POSITION: 1
 COLUMN_DEFAULT: current_timestamp()
...
 


URL: https://mariadb.com/kb/en/now/