How efficient is MYSQL’s in conditional query, and is there a good query optimization scheme? (The specific usage scenario is described in it)

  mysql, question

In my APP, there is a function similar to the prestige circle of friends. Is to be able to view the sharing of friends.
The specific sql statement is probably:

select photo.* from photo where userId in(1,2,3,.........)

In the condition, it is my good friend. This was found out in advance.
There is a puzzle here. Suppose I have 1,000 friends, will the query efficiency be slow?
I don’t know how open source PHP SNS works. .

You great gods should have used everyone’s handfuls!
I have nearly 1,000 friends on top of everyone. So, how does everyone, a good friend, share it?
Alsoselect inThis way?

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