Hello I have a question on how MySQL JOIN has effect on query (search) performance:
Our database consists of about 250.000 datasets (rows). Right now, all of the 150 columns are in one big table. However, we do have certain columns that are empty for most rows (for example information of the status of pictures of customer). Out of the 250.000, only 20.000 have information on photo-status. The idea is to put the columns (amount: 5) about the photo-status in a seperate table to not blow up the database (to normalize the database ?). A search over, lets say, 15 columns, that includes one columns out of the photo-status-columns would then have to JOIN these two tables. Does that lead to performance drop ? Or is maybe even faster to search with a JOIN, because we only have 20.000 rows in that seperate photo-status-table ? What would probably happen if we did this with, lets say, 5 other data-sets (we would the have 7 tables connected through JOIN) ? I hope someone can help me with performance issues about JOIN. Thanks. Flo --------------------------------------------------------------------- Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
