[PHP-DB] Group by

Hi. In a mysql query, it is recommended that "GROUP BY" fields be indexed? Using EXPLAIN on one of my queries, I noticed no change between having indexed by GROUP BY field and not indexing it. Any thoughts would be appreciated. In this example, should `history_field` be indexed...? SELECT MAX(

Re: [PHP-DB] Group by

On Wed, Dec 9, 2009 at 12:52 PM, Philip Thompson wrote: > Hi. > > In a mysql query, it is recommended that "GROUP BY" fields be indexed? Using > EXPLAIN on one of my queries, I noticed no change between having indexed by > GROUP BY field and not indexing it. Any thoughts would be appreciated. >

Re: [PHP-DB] Group by

Hi i recommend always use indexes when programming. developers tend not to.. and when the databases grows it's difficult to modify or make them modify the code. El mié, 09-12-2009 a las 14:22 -0300, Julio Araya escribió: > On Wed, Dec 9, 2009 at 12:52 PM, Philip Thompson > wrote: > > Hi. > > >

Re: [PHP-DB] Group by

Also you may not see a difference because your not even using 'History_field' anywhere in your SELECT statement. I am a little surprised that you didn't receive a error. On Wed, Dec 9, 2009 at 9:31 AM, Juan Pablo Ramirez < ramirez.juanpa...@gmail.com> wrote: > Hi i recommend always use indexes wh

[PHP-DB] Combing PDO with mysql_pconnect connections in one application -- will this degrade performance?

Hi, We are about to convert all of our queries using mysql_pconnect to prepared statements using PDO database connections. It will take some time to convert the hundreds of SQL statements so the plan is to do it in phases. Is is bad idea to have both a mysql_pconnect and a PDO connection op

Re: [PHP-DB] Group by

The only SELECT is on MAX('timestamp'). There is really nothing to Group BY in this query. Dewey Philip Thompson wrote: Hi. In a mysql query, it is recommended that "GROUP BY" fields be indexed? Using EXPLAIN on one of my queries, I noticed no change between having indexed by GROUP BY fiel

[PHP-DB] Combing PDO with mysql_pconnect connections in one application -- will this degrade performance?

Hi, We are about to convert all of our queries using mysql_pconnect to prepared statements using PDO database connections. It will take some time to convert the hundreds of SQL statements so the plan is to do it in phases. Is it a bad idea to have both a mysql_pconnect and a PDO connection open

Re: [PHP-DB] Group by

On Dec 9, 2009, at 12:58 PM, h...@deweywilliams.com wrote: > The only SELECT is on MAX('timestamp'). There is really nothing to Group BY > in this query. > > Dewey > > Philip Thompson wrote: >> Hi. >> >> In a mysql query, it is recommended that "GROUP BY" fields be indexed? Using >> EXPLAIN

Re: [PHP-DB] Group by

Philip Thompson wrote: On Dec 9, 2009, at 12:58 PM, h...@deweywilliams.com wrote: The only SELECT is on MAX('timestamp'). There is really nothing to Group BY in this query. Dewey Philip Thompson wrote: Hi. In a mysql query, it is recommended that "GROUP BY" fields be indexed? Using EXPLA

Re: [PHP-DB] Combing PDO with mysql_pconnect connections in one application -- will this degrade performance?

Sara Leavitt wrote: Hi, We are about to convert all of our queries using mysql_pconnect to prepared statements using PDO database connections. It will take some time to convert the hundreds of SQL statements so the plan is to do it in phases. Is it a bad idea to have both a mysql_pconnect and

Re: [PHP-DB] Combing PDO with mysql_pconnect connections in one application -- will this degrade performance?

> > As long as you test it (hopefully using some sort of automated tests) you > should be right. > > Since you're using persistent connections (make sure you set pdo to do the > same), I don't think you're really doubling the number of connections. Yeah, I think PDO uses the underlying mysql/