Checking value in an array inside one SQL query with WHERE clause

Question

I want to know is this practically possible in sql(using php as server-side), where in you have an array of values(numbers), and you try to retrieve data based on values inside that array..

I have a sql table:

posts(     id int(11) primary key,     posts varchar(140),     user_id int(11) foreign key ); 

I write a query now to retrieve 'posts':

$query="SELECT * FROM posts WHERE user_id=(**Array of select user_id's**)"; 

Is there any sql in-built function to check values inside an array? or should I be using PHP for this?

I am actually trying to implement the twitter model of showing posts of people whom we follow.

Answer 1

Yes, this is easily possible. You need to look at MySQL's IN function

Your query would be something like

SELECT * FROM posts WHERE user_id IN (1,2,3,4,5,6) 

You can build the bit in between the parentheses in PHP using implode()

Answer 2

SQL can't parse PHP arrays. Try this:

$query="SELECT * FROM posts WHERE user_id IN ({implode(',', $userIDarray)})";