Question

I want to import data from MsSQL to HBase running a free form query which has an alias on the key I want to split by. For example my query is:

SELECT       convert(varchar,Table1.Field1) + '_' + Table2.field1 AS 'xyz' 
FROM         Table1
INNER JOIN   Table2 
ON           Table1.field3 = Table2.field4
WHERE        $CONDITIONS

And I want to split work units by this aliased field. So, in my sqoop query I have --split-by 'xyz' option. But, this doesn’t work. I get:

Caused by: com.microsoft.sqlserver.jdbc.SQLServerException: 
Ambiguous column name 'xyz'.

So, how can I make sqoop work with this aliased select field?

Answer 1

This was a limitation of SQL-Server. It doesn’t allow a GROUP BY on an aliased column.

Rewriting the query in the following way helped:

SELECT xyz FROM
(
    SELECT       convert(varchar,Table1.Field1) + '_' + Table2.field1 AS 'xyz' 
    FROM         Table1
    INNER JOIN   Table2 
    ON           Table1.field3 = Table2.field4
) as sub
WHERE $CONDITIONS