Re: How to get the number of records of last 24 hour?

From:

Lew <lew@lewscanon.nospam>

Newsgroups:

comp.lang.java.programmer

Date:

Sun, 08 Jul 2007 12:45:01 -0400

Message-ID:

<NOmdndf1xr4TiQzbnZ2dnUVZ_tfinZ2d@comcast.com>

Cao Yi wrote:

Now, I use java.sql.Timestamp to map column_login_time field whose
type is also timestamp in Mysql.

...

I set the column type in database as TIMESTAMP, and use
java.sql.Timestamp in my Java source code.
Here appends my codes(fragment):

Lew wrote:

Be aware:

MySQL has a type called TIMESTAMP, but it is quite different from the standard TIMESTAMP: It's a 'magic' data type with side effects in that it's automatically updated to the current date and time if some criteria are fulfilled.
MySQL has a type called DATETIME. Like MySQL's TIMESTAMP type, it stores a combination of date and time without fractional seconds. There are no side effects associated with the DATETIME type-which makes it the closest match to the SQL standard's TIMESTAMP type.

from <http://troels.arvin.dk/db/rdbms/#data_types-date_and_time-timestamp>

Cao Yi wrote:

Thanks, Lew! But according to my practise, it was not the same as what
you told!

It's not what I told, it's what's so. I merely conveyed the quoted information.

I insert the timestamp value via JDBC, and the timestamp instance is
generated in Java before inserting!

Then that is not the MySQL TIMESTAMP but the Java class Timestamp (not
"timestamp").

Although MySQL's TIMESTAMP is a 'magic' data type, but it doesn't make
sense.

I do not know what you mean by this sentence.

btw, new Timestamp(System.currentTimeMillis() - 1000*60*60*24)) will
always generate an instance base on current date and time.

The Java type is conformant to the SQL standard. The warning is that the
MySQL TIMESTAMP type is not.

--
Lew