query help

[jcisco2]

I have a table that has the values of:
PalletID, and TransactionType (plus some other data)
but what i want to do is have a query that pulls PalletID that only have a Transaction Type of C and 4. (all tags have this data) here's an example of what i'm looking for.

PalletID transType
1 C
1 3
1 4
1 3
1 4
2 C
2 4
3 C
3 3
3 4

so in my query I want to look at all tags that have only the C then the 4 following it. exclude any pallets that have a 3. so the only tag that should return in the result set would be the palletID of 2. suggestions?

 

[rac2]

SELECT a.PalletID,
       a.transType AS "Type C",
       b.transType AS "Type 3",
       c.transType AS "Type 4"
FROM MyTable a
LEFT JOIN MyTable b ON b.PalletID = a.PalletID
                   AND b.transType = '3'
LEFT JOIN MyTable c ON c.PalletID = a.PalletID
                   AND c.transType = '4'
WHERE a.transType = 'C'

This should yield a result with all of the needed facts in one row. Then add a couple more conditions to obtain just the C4s.

SELECT a.PalletID,
       a.transType AS "Type C",
       b.transType AS "Type 3",
       c.transType AS "Type 4"
FROM MyTable a
LEFT JOIN MyTable b ON b.PalletID = a.PalletID
                   AND b.transType = '3'
LEFT JOIN MyTable c ON c.PalletID = a.PalletID
                   AND c.transType = '4'
WHERE a.transType = 'C'

  AND b.transType IS NULL
  AND c.transType = 4