Repeated Rows Sql Query

Question

I am running a query and I am getting duplicated rows. I dont understand why this is. Here is my Query:

SELECT c.FName,
       p.ProductName,
       s.Description,
       s.Quantity,
       s.Price
FROM   customers c,
       products p,
       sellers s,
       requests r
WHERE  c.ID = s.CID
       AND p.ProductID = s.ProductID
       AND r.ProductID = s.ProductID
       AND r.C_ID = 3
       AND r.MatchType = 'Price'
ORDER  BY s.Price ASC 

=======edit=======

Okay here is an edit of what the values in the Requests table looks like. NOTE: CID 2=DAZ(generally a seller), 3=Paul (Generally purchase guy) and 5= compny1 (generally a seller) NOTE: product id 1= apple, product id 2=pear, productid 3= berries, product id4=orange

The Request table looks like this after selecting records MatchType=Price and cust ID=3:

 requestid |   cid   |   productid   | Quantity | Price  | matchtype
    ------------------------------------------------------------------
    1          3            1            3.0     2.00        price
    3          3            4            4.0     2.50        price
    4          3            3            2.5     2.00        exact  
    5          3            2            3.0     3.50        exact
    6          3            3            3.0     2.00        exact
    7          3            1            10.0    7.00        price  

and here is the sellers table

promotionID |   cid   |   productid   | Quantity | Price | description  
    ------------------------------------------------------------------
    1          2            4            5.0     2.99        oranges
    2          2            3            1.5     1.00        hand strawberries        
    3          2            3            2.5     2.00        l stawberries  
    4          2            2            3.0     3.00        pear       
    5          5            1            5.0     5.00        royal apples fm appleco.         
    6          2            1            6.0     5.50          sweet apples

AFTER RUNNING THE QUERY I HAVE TRIED BOTH THE SUGGESTED JOINS AND THE ONE IN THIS QUESTION I KEEP GETTING THIS AS OUTPUT

FName   ProductName         Description         Quantity    Price

---

daz         Oranges     Fresh and sweet oranges.    5.0        2.99
compny1      Apple      royal apples fm appleco.    5.0        5.00
compny1      Apple      royal apples fm appleco.    5.0      5.00
daz         Apple       sweet apples                 6.0      5.50
daz         Apple       sweet apples                 6.0      5.50

I don't get why I am recieving rows that are repeating. The requested product id must be = sellers product id to match the requested products to the available products and the customerId selected in this case is 3...

I dont get why the last 4 records repeat them self? Why may this be??
Technically speaking only 4 records should be shown. i.e. records on rows.. 1,2 and 3

SUGGESTION/OBSERVATION OKay, After having looked at this... Do you think the rows are repeated because the productID1=apple has been requested by the same customer twice with different quantities???

  requestid |   cid   |   productid   | Quantity | Price  | matchtype
        ------------------------------------------------------------------
    1          3            1            3.0     2.00        price

    7          3            1            10.0    7.00        price  

Answer 1

Your need to use inner join for "filtering" the rows. try this:

select c.FName, p.ProductName, s.Description, s.Quantity, s.Price 
FROM requests r
inner join sellers s on r.ProductID = s.ProductID
inner join products p on p.ProductID=s.ProductID 
inner join customers c on c.ID=s.CID       
where r.C_ID = 3 AND r.MatchType='Price'
ORDER BY s.Price ASC

hope that i don't have any mistake here (its late here), but its the main idea. for columns that exist in two tables and you wish to use the for filtering use inner join, for filtering from one table use the were clause .. (that the theory on one leg) ...

--- edit ----

this query can show the diffidence between the requests ...

select c.FName, p.ProductName, s.Description, s.Quantity, s.Price, r.demandid as 'Request ID'
FROM requests r
inner join sellers s on r.ProductID = s.ProductID
inner join products p on p.ProductID=s.ProductID 
inner join customers c on c.ID=s.CID       
where r.C_ID = 3 AND r.MatchType='Price'
ORDER BY r.demandid s.Price ASC

Answer 2

select c.FName, p.Name, s.Description, s.Quantity, s.Price 
FROM customers c
left join sellers s on c.ID = s.cid
left join requests r on r.ProductID = s.ProductID
left join products p on p.productid = s.productid
where r.C_ID = 1
AND r.MatchType='Price'
ORDER BY s.Price ASC

I setup a fiddle for it SQL Fiddle and threw some dummy data in. The code works if I set the data up correctly.