Mysql – SQL query returning cartesian and duplicates and not single records

So I have four tables as follows:

CREATE TABLE softdrinks (
  drinkID INT NOT NULL AUTO_INCREMENT,
  drinkName VARCHAR(100),
  PRIMARY KEY (drinkID)
  );

 CREATE TABLE categories (
  categoryID INT NOT NULL AUTO_INCREMENT,
  drinkID INT NOT NULL,
  categoryName VARCHAR(100),
  FOREIGN KEY (drinkID) REFERENCES softdrinks(drinkID),
  PRIMARY KEY (categoryID)
  );

  CREATE TABLE staff (
    staffID INT NOT NULL AUTO_INCREMENT,
    staffName VARCHAR(150),
    staffAge INT NOT NULL,
    PRIMARY KEY (staffID)
    );

  CREATE TABLE sold (
    soldID INT NOT NULL AUTO_INCREMENT,
    drinkID INT NOT NULL,
    staffID INT NOT NULL,
    amount INTEGER,
    FOREIGN KEY (staffID) REFERENCES staff(staffID),
    FOREIGN KEY (drinkID) REFERENCES softdrinks(drinkID),
    PRIMARY KEY (soldID)
    );

This is what they look like when I show all the databases on their own:

drinks table:

drinkID drinkName
1        Pepsi
2        Dr Pepper
3        Sprite

categories table:

categoryID  drinkID categoryName
1              1    Cola
2              2    Cola
3              3    Orange

staff table:

staffID staffName   staffAge    gender
1        Bruce         35        MALE
2        Patel         65        MALE
3        Drew          25        MALE

sold table:

soldID  drinkID staffID amount
1           1   1       5
2           1   2       10
3           1   3       25
4           2   2       10
5           3   1       30
6           3   2       14
7           3   3       25

So for drinkID = 1, the sold table gives

soldID  drinkID staffID amount
1         1       1      5
2         1       2      10
3         1       3      25

Basically, I have a complex statement that is fetching all the data as follows:

SELECT tbl_softdrinks.drinkID, tbl_softdrinks.drinkName, 
               (IFNULL(tbl_sold.totalAVG, 0.0)) AS finalAVG, tbl_soldUsers.amount,
               tbl_categories.categoryName, 
               tbl_soldUsers.staffID
                FROM softdrinks tbl_softdrinks
                INNER JOIN categories tbl_categories
                     ON tbl_softdrinks.drinkID = tbl_categories.drinkID
                LEFT JOIN
                     (SELECT tbl_sold.drinkID, ROUND(AVG(tbl_sold.amount),1) AS totalAVG, tbl_sold.amount, 
                        tbl_sold.staffID FROM sold tbl_sold
                      GROUP BY tbl_sold.drinkID) tbl_sold
                     ON tbl_softdrinks.drinkID = tbl_sold.drinkID
                LEFT JOIN
                     sold tbl_soldAmount
                     ON tbl_softdrinks.drinkID = tbl_soldAmount.drinkID
                LEFT JOIN
                     sold tbl_soldUsers
                     ON tbl_softdrinks.drinkID = tbl_soldUsers.drinkID
                INNER JOIN (SELECT DISTINCT staffID, staffName, staffAge FROM staff tbl_staff
                    GROUP BY tbl_staff.staffID) tbl_staff
                    ON tbl_soldUsers.staffID = tbl_staff.staffID
                WHERE tbl_softdrinks.drinkID = 1;

This is returning:

drinkID drinkName   finalAVG    amount  categoryName    staffID
1        Pepsi        13.3        5        Cola           1
1        Pepsi        13.3        5        Cola           1
1        Pepsi        13.3        5        Cola           1
1        Pepsi        13.3        10       Cola           2
1        Pepsi        13.3        10       Cola           2
1        Pepsi        13.3        10       Cola           2
1        Pepsi        13.3        25       Cola           3
1        Pepsi        13.3        25       Cola           3
1        Pepsi        13.3        25       Cola           3

As opposed to:

drinkID drinkName   finalAVG    amount  categoryName    staffID   staffName  staffAge
1        Pepsi        13.3        5        Cola           1       Bruce      35
1        Pepsi        13.3        10       Cola           2       Patel      65
1        Pepsi        13.3        25       Cola           3       Drew       25

This is on sqlfiddle too: http://sqlfiddle.com/#!9/8a6223/9

I believe I am returning cartesian

Would really mean a lot if someone could fix my query, not necessarily database design