NYCPHP Meetup

[nycphp-talk] MySQL doubt

Mark Horton mark at nostromo.net
Fri Jan 14 10:49:07 EST 2005


Sajith A wrote:
> I'm not sure whether i should post this here. Correct me if i'm
> wrong.. I would like to know
> whether there is any performance difference between. "SELECT count(*)
> FROM table" and "SELECT count(field) FROM table".

Mysql has different table types.  MyISAM tables always know the number 
of rows within the table.  The result of "SELECT (*) from table" is 
always known and should return instantly.

This may not work on other table types however.  For instance, it does 
not work for InnoDB tables.

Mark



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