SELECT IN for a large set

Question

In my web application, I want to find out which of the user's Twitter friends already exist on the system ... I am currently working on getting a list of Twitter IDs that the user executes (Twitter API returns 5000 IDs at a time) and execution:

SELECT userId FROM users WHERE userId IN (COMMA_SEPARATED_LIST_OF_IDs);

I don’t like this query, because as the user table grows, this may turn out to be a bottleneck. I don’t want to optimize too, prematurely, is there any other way I have to do this?

Update: I am using MySQL.

Answer 1

Two approaches:

• SELECT IN (expr) SELECT expr. .

• .

Answer 2

Twitter, . , , . API Twitter .

Answer 3

, user.userId . , , . , COMMA_SEPARATED_LIST_OF_IDS ?

Answer 4

EXISTS, Transact SQL. , EXISTS , SQL Server.

http://msdn.microsoft.com/en-us/library/ms188336.aspx