Re: does the number of column affect performance

[Paul DuBois]

On Feb 28, 2012, at 9:59 AM, Zheng Li wrote:

> for example
> there are 2 tables to save same data
> table A has 10 columns: a primary key column and 9 blob column
> table B has 2 columns : a primary key column and 1 blob column which includes all
> data in 2nd~10th columns of table A
> 
> are there any differences in performance when selecting, inserting, updating, and
> deleting data.

Sure. For example, with table A, you can select only those blob columns you're interested
in. With B, you have to select all of them if you want *any* of them.


-- 
Paul DuBois
Oracle Corporation / MySQL Documentation Team
Madison, Wisconsin, USA
www.mysql.com