Question

Here he comes to confuse his day! (should be my handle from now on)

Im confused and very much lost.

I need to figure out how to make a select statement for getting FriendID to relate to there UserID

As you can see FriendID relates to the UserID of my User table, so if FriendID = 2 then display UserID 2 details.

What im trying to do is if im UserID 1 I want to display all my friends, my userid is set by a session,

What I need to do is find out who my friends are so Select FriendID from freinds where SessionID = UserID then some how figure out who friendsID belongs to in the User table and display his firstname, secondname and his picturepath.

Very confusing…

My table structure looks like this:

So to sum it up what I need in my select command:

To find out who im friends with (currentsession UserID has FriendID’s)
Display FirstName, SecondName, picturepath of friendID related to his own UserID

Example:

I (userID=1) have FriendID 2 = UserID 2 so select firstname, secondname from User where UserID=2

I could have relational problems with my table structure tho not sure.

I hope u can understand my confusion:

EDIT for those that cant see the images of my db

    SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0;

SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0;

SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='TRADITIONAL';



CREATE SCHEMA IF NOT EXISTS `gymwebsite2` DEFAULT CHARACTER SET latin1 COLLATE latin1_swedish_ci ;

USE `gymwebsite2` ;



-- -----------------------------------------------------

-- Table `gymwebsite2`.`User`

-- -----------------------------------------------------

CREATE  TABLE IF NOT EXISTS `gymwebsite2`.`User` (

  `UserID` INT NOT NULL AUTO_INCREMENT ,

  `Email` VARCHAR(245) NULL ,

  `FirstName` VARCHAR(45) NULL ,

  `SecondName` VARCHAR(45) NULL ,

  `DOB` VARCHAR(45) NULL ,

  `Location` VARCHAR(45) NULL ,

  `Aboutme` VARCHAR(1045) NULL ,

  `username` VARCHAR(45) NULL ,

  `password` VARCHAR(45) NULL ,

  PRIMARY KEY (`UserID`) )

ENGINE = InnoDB;





-- -----------------------------------------------------

-- Table `gymwebsite2`.`WallPosting`

-- -----------------------------------------------------

CREATE  TABLE IF NOT EXISTS `gymwebsite2`.`WallPosting` (

  `idWallPosting` INT NOT NULL AUTO_INCREMENT ,

  `UserID` INT NOT NULL ,

  `Wallpostings` VARCHAR(2045) NULL ,

  PRIMARY KEY (`idWallPosting`) ,

  INDEX `fk_WallPosting_User` (`UserID` ASC) ,

  CONSTRAINT `fk_WallPosting_User`

    FOREIGN KEY (`UserID` )

    REFERENCES `gymwebsite2`.`User` (`UserID` )

    ON DELETE NO ACTION

    ON UPDATE NO ACTION)

ENGINE = InnoDB;





-- -----------------------------------------------------

-- Table `gymwebsite2`.`Pictures`

-- -----------------------------------------------------

CREATE  TABLE IF NOT EXISTS `gymwebsite2`.`Pictures` (

  `idPictures` INT NOT NULL AUTO_INCREMENT ,

  `UserID` INT NOT NULL ,

  `picturepath` VARCHAR(1045) NULL ,

  PRIMARY KEY (`idPictures`) ,

  INDEX `fk_Pictures_User1` (`UserID` ASC) ,

  CONSTRAINT `fk_Pictures_User1`

    FOREIGN KEY (`UserID` )

    REFERENCES `gymwebsite2`.`User` (`UserID` )

    ON DELETE NO ACTION

    ON UPDATE NO ACTION)

ENGINE = InnoDB;





-- -----------------------------------------------------

-- Table `gymwebsite2`.`Friends`

-- -----------------------------------------------------

CREATE  TABLE IF NOT EXISTS `gymwebsite2`.`Friends` (

  `idFriends` INT NOT NULL AUTO_INCREMENT ,

  `UserID` INT NOT NULL ,

  `FriendID` INT NOT NULL ,

  PRIMARY KEY (`idFriends`) ,

  INDEX `fk_Friends_User2` (`FriendID` ASC) ,

  INDEX `fk_Friends_User1` (`UserID` ASC) ,

  UNIQUE INDEX `FriendID_UNIQUE` (`FriendID` ASC) ,

  CONSTRAINT `fk_Friends_User2`

    FOREIGN KEY (`FriendID` )

    REFERENCES `gymwebsite2`.`User` (`UserID` )

    ON DELETE NO ACTION

    ON UPDATE NO ACTION,

  CONSTRAINT `fk_Friends_User1`

    FOREIGN KEY (`UserID` )

    REFERENCES `gymwebsite2`.`User` (`UserID` )

    ON DELETE NO ACTION

    ON UPDATE NO ACTION)

ENGINE = InnoDB;







SET SQL_MODE=@OLD_SQL_MODE;

SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS;

SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS;

Answer 1

select u.FirstName, u.SecondName, p.picturePath
from User u
join Friends f
  on f.FriendId = u.UserId
join Pictures p
  on p.UserId = u.UserId
where f.UserId = SessionId ( <-- sessionId is your id)