Re: [GENERAL] Typecasting datetype as date. How do I cope with NULLs?

>>>>> "WC" == Wim Ceulemans <wim.ceulemans@nice.be> writes:


 WC> I find the above interesting and I've tried something similar that won't
 WC> work.
 WC> I have two tables defined as follows

 WC> create table test1 (id1 int,link1 int);
 WC> create table test2 (id2 int, field2 varchar(5));

 WC> where link1 is a foreign key of test1 that should be linked to id2 of test2

 WC> Now when I execute the following query:

 WC> select id1,field2,link1 from test1,test2 where test1.link1=test2.id2
 WC> union
 WC> select id1,NULL,link1 from test1;

 WC> I always get the following error:

 WC> Each UNION query must have identical target types.

 WC> Why this error, and what does it mean?

Pehaps this is a bug fixed in 6.4 version? I saw this message when
before upgrating to 6.4. You can modify query so:

select id1,field2,link1 from test1,test2 where test1.link1=test2.id2
 union
select id1, -1, link1 from test1;

where -1 is value non present in field2 domain.

--
Anatoly K. Lasareff              Email:       tolik@icomm.ru
Senior programmer