Question

I have three tables with a one to many relationship as shown below. What I would like to do is select all the data from “tblOne” based on their relationship to “tblThree”.

So without having a query to get all tblTwoIDs I would like to select from tblOne where tblThreeID equals an “Inputed Value”

Hope this makes sense,

Thanks
Ben

tblOne

tblOneID

data

tblTwoID

---

tblTwo

tblTwoID

data

tblThreeID

---

tblThree

tblThreeID

data

Answer 1

SELECT tblOne.*  -- use "SELECT DISTINCT tblOne.*" to avoid duplicate results
FROM tblOne
    INNER JOIN tblTwo
        ON tblOne.tblTwoID = tblTwo.tblTwoID
    INNER JOIN tblThree
        ON tblTwo.tblThreeID = tblThree.tblThreeID
WHERE tblTwo.tblThreeID = 42  -- replace "42" with the id you want to find

If you don’t need to ensure that the records exist in tblThree then you don’t need to join to it at all:

SELECT tblOne.*  -- use "SELECT DISTINCT tblOne.*" to avoid duplicate results
FROM tblOne
    INNER JOIN tblTwo
        ON tblOne.tblTwoID = tblTwo.tblTwoID
WHERE tblTwo.tblThreeID = 42  -- replace "42" with the id you want to find