Query multilayer table in sql - sql

Question

I am trying to retrieve the UserInfo with the UserId=10004 with all his friends and all the posts of his friends and all the likes on those posts. And for that I am using a query :
select *,
(select * ,
(select * ,
(select * from PostLikes where PostId=UserPosts.PostId) as likes
from UserPosts where UserId=FriendsRelation.PersonId1 or UserId=FriendsRelation.PersonId2) as posts
from FriendsRelation where PersonId1=UserId or PersonId2=UserId) as friends
from UserInfo
where UserId=10004
but it is returning with an error
Only one expression can be specified in the select list when the subquery is not introduced with EXISTS
How can I solve it?
Here are the tables that I am using:
CREATE TABLE [dbo].[UserInfo]
(
[UserId] [bigint] IDENTITY(1,1) NOT NULL,
[Username] [nvarchar](max) NULL,
[Email] [nvarchar](max) NOT NULL,
[UserPassword] [nvarchar](max) NOT NULL,
[Name] [nvarchar](max) NULL,
[Gender] [nchar](10) NOT NULL,
[ContactNo] [bigint] NOT NULL,
[DateOfBirth] [date] NOT NULL,
[RelationshipStatus] [nchar](10) NULL,
[InterestedIn] [nchar](10) NULL,
[Address] [nvarchar](max) NULL,
[Country] [nchar](10) NOT NULL,
[FavouriteQuote] [nvarchar](max) NULL,
[DisplayPhoto] [nvarchar](max) NULL,
[Guid] [nvarchar](max) NOT NULL,
[Status] [tinyint] NOT NULL CONSTRAINT [DF_UserInfo_Status] DEFAULT ((1)),
[CreatedDate] [datetime] NOT NULL,
[LastLogIn] [datetime] NULL,
CONSTRAINT [PK_UserInfo]
PRIMARY KEY CLUSTERED ([UserId] ASC)
WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF,
IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON,
ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
UserPosts table:
CREATE TABLE [dbo].[UserPosts]
(
[PostId] [bigint] IDENTITY(1,1) NOT NULL,
[UserId] [bigint] NOT NULL,
[PostText] [nvarchar](max) NULL,
[PostPicture] [nvarchar](max) NULL,
[Time] [time](7) NOT NULL,
[Date] [date] NOT NULL,
[LikeCount] [int] NULL CONSTRAINT [DF_UserPosts_LikeCount] DEFAULT ((0)),
CONSTRAINT [PK_UserPosts]
PRIMARY KEY CLUSTERED ([PostId] ASC)
WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF,
IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON,
ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
GO
ALTER TABLE [dbo].[UserPosts] WITH CHECK
ADD CONSTRAINT [FK_UserPosts_UserInfo]
FOREIGN KEY([UserId]) REFERENCES [dbo].[UserInfo] ([UserId])
ON DELETE CASCADE
GO
ALTER TABLE [dbo].[UserPosts] CHECK CONSTRAINT [FK_UserPosts_UserInfo]
GO
and PostLikes table:
CREATE TABLE [dbo].[PostLikes]
(
[LikeId] [bigint] IDENTITY(1,1) NOT NULL,
[PostId] [bigint] NOT NULL,
[UserId] [bigint] NOT NULL,
CONSTRAINT [PK_PostLike]
PRIMARY KEY CLUSTERED ([PostId] ASC, [UserId] ASC)
WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF,
IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON,
ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
ALTER TABLE [dbo].[PostLikes] WITH CHECK
ADD CONSTRAINT [FK_PostLikes_UserInfo]
FOREIGN KEY([UserId]) REFERENCES [dbo].[UserInfo] ([UserId])
GO
ALTER TABLE [dbo].[PostLikes] CHECK CONSTRAINT [FK_PostLikes_UserInfo]
GO
ALTER TABLE [dbo].[PostLikes] WITH CHECK
ADD CONSTRAINT [FK_PostLikes_UserPosts]
FOREIGN KEY([PostId]) REFERENCES [dbo].[UserPosts] ([PostId])
ON DELETE CASCADE
GO
ALTER TABLE [dbo].[PostLikes] CHECK CONSTRAINT [FK_PostLikes_UserPosts]
GO

Answer 1

Similar to other people's answers, but use left joins for everything (in case the user has no friends), and some changes to join logic.
declare #userID int = 10004 --For easy swapping out if you want to query someone else
Select * from UserInfo a
left join FriendsRelation b
on b.PersonID1 = #userID or b.PersonID2 = #userID --Faster than joining and then filtering, if you're only looking for one person at a time
left join UserPosts c
on (c.UserID = b.PersonID1 or c.UserID = b.PersonID2)
and c.UserID <> #userID --returns only friends' posts, not user's posts, as specified in original question
left join postLikes d
on d.PostID = c.PostID
where a.UserID = #userID

Answer 2

You can use JOINS like this:
select *
from UserInfo
inner join FriendsRelation on UserInfo.UserId = FriendsRelation.PersonId1 or UserInfo.UserId = FriendsRelation.PersonId2
inner join UserPosts on FriendsRelation.PersonId1 = UserPosts.UserId
inner join PostLikes on UserPosts.PostId = PostLikes.PostId
where UserInfo.UserId=10004

Answer 3

As already mentioned, you need to use join instead of subqueries. Probably this query will be useful for you
select *
from UserInfo
inner join FriendsRelation
on UserInfo.UserId = FriendsRelation.PersonId1
inner join UserPosts
on FriendsRelation.PersonId1 = UserPosts.UserId
left outer join PostLikes
on UserPosts.PostId = PostLikes.PostId
where UserInfo.UserId=10004
union
select *
from UserInfo
inner join FriendsRelation
on UserInfo.UserId = FriendsRelation.PersonId2
inner join UserPosts
on FriendsRelation.PersonId2 = UserPosts.UserId
left outer join PostLikes
on UserPosts.PostId = PostLikes.PostId
where UserInfo.UserId=10004