>>

>>PartId     PartNo  SerialNo     Sequence
>>1          AS345   ANB-121             1
>>2          AS345   ANB-122             2
>>3          AS345   ANB-123             3
>>4          AS345   ANB-124             4
>>5          A34SF   1212544             1
>>6          B21AC   ANB-A1              1
>>7          B21AC   ANB-A2              2
>>8          ANG34   ANG34               1
>>

>>
>>From the above set the query should return rows 5 and 8 because those partnumber/serialno combinations only appear once.
>
>But they are all unique?
>What makes rows 5 and 8 different?
>Maybe because there is no other rows with the same PartNo?

It looks like they have some common part of SerialNo, such as ANB-