Обсуждение: Creste Index with nullable

Hi,

I have a question!

create table test (
   code int not null,
   name varchar(40) not null,
   last_name varchar(40)    {this field is nullable}
)

I can create a index like
"CREATE INDEX idx_test  ON etqmov  USING btree  (name, last_name)"
using a nullable field? Will work fine?

Thanks...
Diego Ziquinatti
 From Brazil

Diego <diego@unimedijui.com.br> writes:
> I can create a index like
> "CREATE INDEX idx_test  ON etqmov  USING btree  (name, last_name)"
> using a nullable field? Will work fine?

Sure.  Note however that "last_name IS NULL" is not an indexable
operation, so you won't be able to use the index to search for rows
containing nulls.  This may or may not matter to you, but if it does
you'll need to think of another way to locate those rows.  (Some people
solve this sort of problem with partial indexes.)

            regards, tom lane