5

My interest is to store the time with FSP of 6. As I've read, this cannot be achieved with TIMESTAMP or DATETIME data types. So, I have a double field to store the output of the microtime function.

Is there anyway I can set (or even write some code to create) a default value for such a field?

I want to use something like NOW(6) and get 1442059062.065123 for example.

2 Answers 2

6

You could format it with UNIX_TIMESTAMP like below:

mysql> SELECT UNIX_TIMESTAMP(NOW(6));
+------------------------+
| UNIX_TIMESTAMP(NOW(6)) |
+------------------------+
|      1442068528.543100 |
+------------------------+
1 row in set (0,00 sec)

mysql> 

You can find any others date and time functions here. You could add a trigger and if you want a default value for your decimal(16, 6) microtime, use BEFORE INSERT and replace your NEW.bigintvalue=UNIX_TIMESTAMP(NOW(6));.

Example:

mysql> CREATE TABLE `test`.`test1` (
    ->   `id` INT NOT NULL AUTO_INCREMENT,
    ->   `time` DECIMAL(16, 6) NULL,
    ->   PRIMARY KEY (`id`));
Query OK, 0 rows affected (0.01 sec)

mysql> 
mysql> DELIMITER //
mysql> CREATE DEFINER=`root`@`localhost` TRIGGER `test`.`test1_BEFORE_INSERT` BEFORE INSERT ON `test1` FOR EACH ROW
    -> BEGIN
    -> SET NEW.time=UNIX_TIMESTAMP(NOW(6));
    -> END
    -> //
Query OK, 0 rows affected (0.00 sec)

mysql> DELIMITER ;
mysql> 
mysql> # Adding 1 into id field
mysql> INSERT INTO `test`.`test1` (`id`) VALUES ('1');
Query OK, 1 row affected (0.00 sec)

mysql> select * from test.test1;
+----+-------------------+
| id | time              |
+----+-------------------+
|  1 | 1442069359.675330 |
+----+-------------------+
1 row in set (0.00 sec)

mysql> 
1
  • Isn't there anyway of saying UNIX_TIMESTAMP(NOW(6)) as the default for the field?
    – Victor
    Sep 13, 2015 at 8:59
4

Perhaps you want DOUBLE? Or DECIMAL(16,6)?

SELECT UNIX_TIMESTAMP(NOW()), UNIX_TIMESTAMP(NOW(6));
+-----------------------+------------------------+
| UNIX_TIMESTAMP(NOW()) | UNIX_TIMESTAMP(NOW(6)) |
+-----------------------+------------------------+
|            1442099776 |      1442099776.196746 |
+-----------------------+------------------------+

Or multiply by 1000000 and use BIGINT?

SELECT 1000000 * UNIX_TIMESTAMP(NOW(6));
+----------------------------------+
| 1000000 * UNIX_TIMESTAMP(NOW(6)) |
+----------------------------------+
|          1442099987061904.000000 |
+----------------------------------+

(the decimal places will vanish when storing into a BIGINT.)

1
  • Although this is the way I want to store dates (with 6 decimals), @oNare's answer is the one that fits me, because he showed me how to add the DEFAULT value definer for my field
    – Victor
    Sep 13, 2015 at 7:40

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