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 -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql
