Hello all. Well I posted this question at forums.mysql.com but got no answer thought I'd try the experts here
Theoretically speaking, wouldn't combining queries have an adverse effect on performance due to less use of the query cache?
For example, let's assume we have three tables: A, B, and C. Table C gets updated frequently while table A and B do not. Now is it not correct to conclude that..
A query, which SELECTS results from all three tables would have to execute in its entirety (ignoring query cache) every time table C gets updated. However, having three different queries in your code would register two query cache hits (table A & B queries) and only the table C query would execute often.
The reason I ask is that I've been working to combine queries for better performance but now I'm thinking I should avoid complex queries which use multiple tables (since some of those tables get frequent updates).