Torsten Curdt dijo: >> WHAT IS WRONG? >> >> In example A all is OK. >> >> In example B we are not using the power of the Database Manager. >> >> WHY? >> >> The LIMIT clause was designed to tell the database engine: >> >> "Let find just X rows", then the database engine when it got the X >> rows stop searching and return the X rows. It improves the response >> time, since does not to continue searching! >> >> Now think in a 10 million row table and YOU KNOW you need only 5 rows! > > whether 10 million rows or not - the current sollution will only ask for > 6 - one additional row. Is that the time penalty you are talking about?
Yes, because you already know that there are only 5 rows for every register. Then the database will search the last 6th row that no exist. Forcing to searh in the ENTIRE table. Maybe your 5 rows are at the beginning of the table but the non existent 6th row will force the Database Engine to search for this. Antonio Gallardo. > -- > Torsten > > > --------------------------------------------------------------------- To > unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, email: [EMAIL PROTECTED] --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, email: [EMAIL PROTECTED]
