Question

I have 3 tables I am working with.

TableA, TableB, TableC

TableA contains the information for the client, each row contains all the information for one specific person.

TableB contains information for a message a person in TableA created.

ID  DistID  Subject Message CreatedDate StatusID    SentTotal
57  3   MonList MonList 2012-03-19 16:21:36.117 2   4

TableC contains a list of people who have access to the message in TableB.

ID     MessageID    DistID  StatusID  Important  OriginalMessagelID
25111   58            516       1          0       NULL
25112   58            519       1          0       NULL
25114   58            374       1          0       NULL
25115   58            5545      1          0       NULL
25116   58            23435     1          0       NULL

TableC MessageID will be the same as TableB ID.

TableB and TableC DistID will reference the DistID in TableA (table A included way to much info to copy for even a single row, it is a 1 to 1 ratio, 1 row for one customer).

I need to produce a query that links these three tables together. Here is what I have so far:

SELECT *
FROM Distributor d
INNER JOIN Messages ms
    ON ms.DistID = d.DistID
INNER JOIN Message m
    ON m.DistID = d.DistID
WHERE ((d.DCLoginDate <= (GETDATE() - 3) OR d.DCLoginDate IS NULL) AND (CONVERT(VARCHAR(8), m.CreatedDate, 1)) = (CONVERT(VARCHAR(8), GETDATE(), 1)))

Now TableB can have multiple messages created by the same customer, so their DistID can be present in this table more than 1 time.

TableC is the same way, the DistID can be present in this table more than one time.

I started making individual queries that worked:

SELECT *
FROM Distributor
WHERE (DCLoginDate <= (GETDATE() - 3) OR DCLoginDate IS NULL)

SELECT *
FROM Message m
INNER JOIN Messages ms
    ON ms.MessageID = m.ID
WHERE ((CONVERT(VARCHAR(8), CreatedDate, 1)) = (CONVERT(VARCHAR(8), GETDATE(), 1)))

The above work correctly, when I tried to combine them into one statement, it started returning 0 results when i should have returned two (from my live data, not the data provided above).

Anyone understand how to get this to work effeciently?

Answer 1

Your join conditions were different between the single query and the individual queries… What about this?

SELECT *
FROM Distributor d
INNER JOIN Messages ms
   ON ms.DistID = d.DistID
INNER JOIN Message m
   ON m.ID = ms.MessageID
WHERE 
   ((d.DCLoginDate <= (GETDATE() - 3) OR d.DCLoginDate IS NULL) AND 
   (CONVERT(VARCHAR(8), m.CreatedDate, 1)) = (CONVERT(VARCHAR(8), GETDATE(), 1)))