even if I select all columns every time no matter it is Table A or B,
A has better performance?
On 2012/02/29, at 4:41, Paul DuBois wrote:
>
> 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
>
