Question

I have 2 tables

Table A

NameID  FirstName  MiddleName  LastName  Addr1  Addr2  Phn1  Phn2  City  State 
NULL      Micheal    Calvin      Dodson    12     23     1234  123  XYZ   ABC    
NULL      John       NULL        Keith     NULL   NULL   2344  NULL SQE   FDG    
NULL      John       NULL        Keith     NULL   NULL   2344  NULL SQE   FDG 
NULL      William    Stephen     NULL      45     NULL   NULL  NULL HJD   ABC
NULL      Victor     NULL        Anthony   NULL   NULL   NULL  NULL NULL  NULL

Table B

NameID   FirstName  MiddleName  LastName  Addr1  Addr2  Phn1  Phn2  City State Zip Email Gender...

I need to get the distinct records of (FirstName,MiddleName,LastName) of Table A and insert the same details along with the other fields matching with Table A into Table B.
My Table B has NameID as an identity coloum. So after inserting a unique record into Table B, I need to get that NameID and insert it back into Table A shown below :

TABLE A

Table A

NameID  FirstName  MiddleName  LastName  Addr1  Addr2  Phn1  Phn2  City  State 
1         Micheal    Calvin      Dodson    12     23     1234  123  XYZ   ABC    
2         John       NULL        Keith     NULL   NULL   2344  NULL SQE   FDG    
2         John       NULL        Keith     NULL   NULL   2344  NULL SQE   FDG 
3         William    Stephen     NULL      45     NULL   NULL  NULL HJD   ABC
4         Victor     NULL        Anthony   NULL   NULL   NULL  NULL NULL  NULL

TABLE B

NameID  FirstName  MiddleName  LastName  Addr1  Addr2  Phn1  Phn2  City State Zip  Email Gender...
1       Micheal    Calvin      Dodson    12     23     1234  123   XYZ   ABC   NULL NULL  NULL
2       John       NULL        Keith     NULL   NULL   2344  NULL  SQE   FDG   NULL NULL  NULL
3       William    Stephen     NULL      45     NULL   NULL  NULL  HJD   ABC   NULL NULL  NULL
4       Victor     NULL        Anthony   NULL   NULL   NULL  NULL  NULL  NULL  NULL NULL  NULL

Can you please help me with this. Im not able to get this query right. Code in SQL Server 2008

Thanks in advance,
Sunitha

Answer 1

I think the easiest way to do this is with two queries. The first problem is handling duplicates in TableA. The following query selects an arbitrary row for each name combination:

insert into TableB()
select ()
from (select a.*,
row_number() over (partition by FirstName, MiddleName, LastName order by FirstName) as seqnum
from TableA a
) a
where seqnum = 1

Then, update the original table:

update TableA
    set NameId = (select max(NameId) from TableB
                  where TableB.FirstName = TableA.FirstName and
                        TableB.MiddleName = TableA.MiddleName and
                        TableB.LastName = TableA.LastName
                 )
    where NameId is null

If your fields contain NULL values (rather than blanks), you can use coalesce() for the join conditions:

update TableA
    set NameId = (select max(NameId) from TableB
                  where coalesce(TableB.FirstName, '<null>') = coalesce(TableA.FirstName, '<null>') and
                        coalesce(TableB.MiddleName, '<null>') = coalesce(TableA.MiddleName, '<null>') and
                        coalesce(TableB.LastName , '<null>')= coalesce(TableA.LastName, '<null>')
                 )
    where NameId is null