MySQL Forums
Forum List  »  Performance

Re: distinct clause issue for 600000 records
Posted by: Ra Nala
Date: November 16, 2015 04:12AM

Øystein Grøvlen Wrote:
-------------------------------------------------------
> Hi,
>
> I am not sure what "distinct clause issue"

Okay, my question is .... is it good practice to write the DISTINCT in extraction (select query) or not ?. as per my DBA input it is bad practice , his suggestion was, instead of DISTINCT better to write sub select query to avoid duplicates.

>
> I do not understand what you mean by "Cardinality
> length"

generally when we create foreign key relation ship between master and child tables then be default Cardinality will be created based on 1:1 or 1:n in this way.

as per my DBA input, in my database, large size was created for Cardinality length, and his suggestion is,better to reduce the Cardinality length so that performance will be improved.

I hope you are able to understand the my inputs.

Options: ReplyQuote


Subject
Views
Written By
Posted
1013
November 12, 2015 03:20AM
1005
November 13, 2015 12:37AM
1008
November 13, 2015 05:56AM
1074
November 13, 2015 07:15AM
Re: distinct clause issue for 600000 records
999
November 16, 2015 04:12AM


Sorry, you can't reply to this topic. It has been closed.

Content reproduced on this site is the property of the respective copyright holders. It is not reviewed in advance by Oracle and does not necessarily represent the opinion of Oracle or any other party.