Very Computer

And then, I execute the following statment but get the ORA-01790 error.

sql > select A.mem_id , B.mem_id From gmember A, gmember B
    where A.mem_id =1 and B.mem_gid = A.mem_id
UNION
select A.mem_id , NULL From gmember A
    where A.mem_id =1 ;

select A.mem_id , B.mem_id From gmember A, gmember B
                            *
ERROR at line 1: ORA-01790: expression must have same datatype as
corresponding expression

--------

Any suggestion is appreciated. Thank you.

Chris

Quote:> I create a table with the following structure :
> sql > create table  gmember (mem_id NUMBER(38), mem_group_id NUMBER
(38));
>      > insert into gmember (1, NULL);
>      > insert into gmember (2,1);
>     >commit;

> And then, I execute the following statment but get the ORA-01790
error.

> sql > select A.mem_id , B.mem_id From gmember A, gmember B
>     where A.mem_id =1 and B.mem_gid = A.mem_id
> UNION
> select A.mem_id , NULL From gmember A
>     where A.mem_id =1 ;

> select A.mem_id , B.mem_id From gmember A, gmember B
>                             *
> ERROR at line 1: ORA-01790: expression must have same datatype as
> corresponding expression

> --------

> Any suggestion is appreciated. Thank you.

> Chris

select A.mem_id , B.mem_id
  from gmember A, gmember B
  where A.mem_id = 1 and B.mem_gid = A.mem_id
UNION
select A.mem_id , TO_NUMBER(NULL)
  from gmember A
  where A.mem_id = 1;

Lev Smirnov
Brainbench MVP for Oracle admin
http://www.brainbench.com

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Thanks.

null + 0

instead.

Martin