Select * or select this, this this, this

[TEENFRONT]

Hey

 

This maybe a stupid question, but everyone i look people seem to only SELECT * FROM ... even in tutorials...

 

and therefore,thats what iv been doing for the last year... but our site is rather big and im thinking the little * is pulling waaay to much info than it needs, so i went through and converted * to specific columns that i need..its going to be a few days till i can see if this made an impact..

 

Server wise, will switching from * to specific columns needed make a difference? as id imagine with just selecting specific colums, it might take a little more processing to be specific, rather than * just pulls the whole lot..?

[Mchl]

Quite contrary. Selecting only certain columns is actually faster.

[TEENFRONT]

thats what i was hoping for

 

so selecting certain colums do i still do this to get the content?

 

SELECT usernick, games_won, games_payed, tname FROM table

while($row = mysql_fetch_array($result)){

  $_SESSION['nickname'] = $row['usernick'];
  $_SESSION['played'] = $row['games_played'];
  $_SESSION['won'] = $row['games_won'];
  $_SESSION['tname'] = $row['tname'];

}

 

or would the columns already be in an array?

 

also, if theres only one result set returned, im guessing i dont need the while statement?

[Mchl]

If there's only one result, while() is unnecessary.... you will save a microsecond or two

You still need $row = mysql_fetch_array($result) and assigning variables to $_SESSION

[TEENFRONT]

every micro second helps when its been loaded hundreds of thousands of times lol. Thats great thanks very much!

[Mchl]

The most potential savings in time, when working with database, are in optimising queries and database design. For example creating an index where needed can give 10-fold or more decrease in query execution time.

[kickstart]

Hi

 

As above. Also if you use SELECT * and the layout of the database changes then you can have unforseen effects (especially if you refer to column numbers rather than names). Also if you have a table join and a column is added to one table that has the same name as a column in the other table then again you can have unexpected abends in the future.

 

All the best

 

Keith