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From:Zheng Li Date:February 29 2012 1:55am
Subject:Re: does the number of column affect performance
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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
> 

Thread
does the number of column affect performanceZheng Li28 Feb
  • Re: does the number of column affect performancePaul DuBois28 Feb
    • Re: does the number of column affect performanceMichael Dykman28 Feb
    • Re: does the number of column affect performanceZheng Li29 Feb
      • Re: does the number of column affect performanceBaron Schwartz29 Feb
        • Re: does the number of column affect performanceJohan De Meersman1 Mar
    • Re: does the number of column affect performanceZheng Li9 Mar
      • Re: does the number of column affect performanceZheng Li9 Mar