Does the order of the rows inside a table matter?

[Zoruglu]

Hello!

If I create a table like this:

CREATE TABLE zapi_sessions (
  id varchar(32) NOT NULL default '0',
  user_name varchar(64) default NULL,
  user_id mediumint(8) NOT NULL default '0',
  ip_address varchar(16) default NULL,
  browser varchar(64) default NULL,
  running_time int(10) default NULL,
  login_type char(3) default '',
  location varchar(40) default NULL,
  user_group smallint(3) default NULL,
  PRIMARY KEY  (id),
  KEY in_topic (in_topic),
  KEY in_forum (in_forum)
);

Does it matter in what order the rows inside this table (or any table forthat matter) are created?

[bradgrafelman]

What do you mean "the order of the rows?" I know of no issue that would arise from rows being "out of order."

I know you can run an 'ALTER TABLE zapi_sessions ORDER BY id ASC' if you want to order the rows as such, other than that, I'm not quite sure what you mean.

[Zoruglu]

Oh, I mean, when a table is created like this:

CREATE TABLE zapi_sessions (
  id varchar(32) NOT NULL default '0',
  user_name varchar(64) default NULL,
  user_id mediumint(8) NOT NULL default '0',
  user_group smallint(3) default NULL,
  running_time int(10) default NULL,
  location varchar(40) default NULL,
  ip_address varchar(16) default NULL,
  browser varchar(64) default NULL,
  login_type char(3) default '',
  PRIMARY KEY  (id),
  KEY in_topic (in_topic),
  KEY in_forum (in_forum)
);

or like this

CREATE TABLE zapi_sessions (
  id varchar(32) NOT NULL default '0',
  user_name varchar(64) default NULL,
  user_id mediumint(8) NOT NULL default '0',
  ip_address varchar(16) default NULL,
  browser varchar(64) default NULL,
  running_time int(10) default NULL,
  login_type char(3) default '',
  location varchar(40) default NULL,
  PRIMARY KEY  (id),
  KEY in_topic (in_topic),
  KEY in_forum (in_forum)
);

both tables are identical, however the rows created in them have a different order...

So I was wondering if the order of the rows inside a table matter? For exemple for performance issues when using the tables? Or other things or issues?

[bradgrafelman]

Nope. If you do a "SELECT *" it loads all the rows.. order doesn't matter. If you do a "SELECT <ColumnName>" it just selects the one column.

Also - I think you're confusing "rows" with "columns!"

[Zoruglu]

Yes you are right, I ment rows. Thanks for the answer! 🙂

[bradgrafelman]

Erm... no.. you meant columns...

[Zoruglu]

hahahaha! I guess it has been a long night, columns 😃

I'm off to bed now 🙂