The difference between MySQL 5.5 and 5.6 timestamp field DEFAULT current_timestamp on UPDATE current_timestamp

Http://www.111cn.net/database/mysql/55392.htm

This article is to give you the difference between MySQL 5.5 and 5.6 timestamp field DEFAULT current_timestamp on UPDATE current_timestamp, I hope this tutorial will be helpful to you.

mysql5.6 Database:

The code is as follows

Copy Code

[bighd" ([email protected] ) [cm]> SELECT version (); +------------+ | version ()   | +------------+ | 5.6.13-log | +------------+ 1 ROW in SET (0.02 sec)   [BIGHD] ([email protected]) [cm]> ALTER TABLE S__uk ADD ' Last_op_time ' TIMESTAMP not NULL DEFAULT current_timestamp on UPDATE current_timestamp; Query OK, 0 ROWS Affected (0.99 sec) records:0  duplicates:0  warnings:0   [BIGHD] ([email& Nbsp;protected]) [cm]> SELECT ID, last_op_time from s__uk  LIMIT 1; +----+---------------------+ | id | last_op_time        | +----+---------------------+ |  1 | 2013-10-10 10:17:57 | +----+---------------------+ 1 ROW in SET (0.00 sec)

mysql5.5 Database:

The code is as follows

Copy Code

([email protected]) [cm]> SELECT version (); +------------+ | Version () | +------------+ | 5.5.15-log | +------------+ 1 ROW in SET (0.00 sec) ([email protected]) [cm]> ALTER TABLE s__uk ADD ' last_op_time ' TIMESTAMP not NULL DEFAULT current_timestamp on UPDATE current_timestamp; Query OK, 2523 ROWS Affected (0.99 sec) records:2523 duplicates:0 warnings:0 ([email protected]) [cm]> SELECT last_op_time from S__uk LIMIT 1; +---------------------+ | Last_op_time | +---------------------+ | 0000-00-00 00:00:00 | +---------------------+ 1 ROW in SET (0.00 sec)

Also, have you ever considered what would happen if you only update this field? Will it be the specified time, or is it automatically generated?

copy code

([email protected]) [cm]> UPDATE s__uk SET last_op_time= ' 2012-12-12 00:00:00 ' WHERE id=1; Query OK, 1 ROW affected (0.07 sec) ROWS matched:1  changed:1  warnings:0   ([EMAIL PR Otected]) [cm]> SELECT ID, last_op_time from s__uk  LIMIT 1; +----+---------------------+ | id | last_op_time        | +----+---------------------+ |  1 | 2012-12-12 00:00:00 | +----+---------------------+ 1 ROW in SET (0.01 sec)

Did you get the right wood?

Ps:
How do I tell if a field has multibyte characters (such as Chinese)?

Character_length (value) = LENGTH (value) does not contain multibyte characters.

Length is a byte bytes long and character_length is the character characters length.

PS2:
MongoDB Find ()

After that, the function to beautify/format the output is:
Db.tbl.find (). Pretty ()

? http://www.111cn.net/database/mysql/55392.htm