I am working on a web application (PHP/MySQL) and I am looking for the best performance.
I am building a view, in this view I have to join multiple data but I was wondering, what is the best choice between joining a view with another view or with tables.
To be more clear, if i have:
View_1 = Table_A join Table_B
And i need in View_2 data from Table_A and Table_B, should I do
View_2 = Table_C join View_1 OR View_2 = Table_C join Table_A join Table_B
Thank you very much
分享 Look at the explain plan for your specific query.
Joining to a view rather than the underlying tables might have an impact on performance--because, as Atip Roy explains, the order in which you perform joins can be important for performance, and having some of the joins within a view could prevent you from optimally ordering the joins in the query.
But this depends entirely on your query--it might not make any difference.
And, there is a benefit to using a view, as well: it means the logic of that view is stored in only one place. You have given us a simplified example, but in real life, the code for view 1 is likely more complex. If you need the same logic in multiple places, it's a good thing to avoid code duplication where possible.
So, I would check whether performance actually matters (and how much it matters). I would prefer to use the view unless the performance of that option was not acceptable.
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