Question

Oke my website works with Facebook Api, it will import all the friends (userId, name) of the user that will be logged in so my table structure is as following:

users: id, name
usersFriends: id, friendUserId, name

So when the users join the website, they will get all the friends imported, example data:

user: 237374734 (facebook user id), John brouwers (name of the user)

then it will import all the friends of John. for example:

userFriends: 237374734 (John user id), 2737373, Michael jackson

Now what I need is a query that will SEARCH (by name) through the friends, which is
no problem with just a join, but what I need is in the query I need to CHECK whether the user is on my website so lets take an example:

We logged in with the user John, and we are searching for michael so that would be

SELECT name FROM userFriends WHERE name LIKE %michael%

But what I need is NOT only return the name of the user, I also need a CHECK whether the user exists in the users table.

Sorry for the long story, hope that my question is clear. Thanks already!

Answer 1

Edit: So you need a query that search friends by Name and check whether the friend exists in the users table or not, As follows:

create table Users(
   Id int not null,
   primary key (Id),
   Name varchar(50) not null
)TYPE=MyISAM;
create table UserFriends(
   Id int not null,
   foreign key (Id) references Users(Id),
   FriendUserId int not null,
   Name varchar(50) not null
)Type=MyISAM;
insert into Users(Id,Name) values(237374734,'John brouwers');
insert into UserFriends(Id,FriendUserId,Name)
values(237374734, 2737373, 'Michael jackson');

Here is the query that will search for the suer that his name like "%Michael%" and check if he is a registered user or not:

select s.Id, s.Name, 
       case when exists 
       ( 
           select Name from users where Name like "%Michael%" 
       ) Then 'Registered User'
       else
       (
           'Not Registered'
       )
       end
       as 'Is Registered in My Website'
from 
(
      select uf.FriendUserId Id, uf.Name
      from UserFriends uf
      left join users u on u.Id = uf.friendUserId
      where uf.name like "%Michael%"
) s

This will gives you:

Id              Name        Is Registered in My Website
2737373   Michael jackson        Not Registered

Hope this will be helpful and if there is any problems don’t hesitate to ask.