Creating sql statements to return information from a table - datatable

Question

I am creating sql queries to return information from a table, but I am having issues with one in particular. I want to return all of the urban areas that are in the country of colorado.
The actual definition of the query is
Return the names (name10) of all urban areas (in alphabetical order) that are entirely contained
within Colorado. Return the results in alphabetical order. (64 records)
The tables that I am using are tl_2010_us_state10 (this stores information for the states). I think I am going to use the name10 variable in this table because that has all of the names of the states.
Table "public.tl_2010_us_state10"
Column | Type | Modifiers
------------+-----------------------------+-------------------------------------
gid | integer | not null default
region10 | character varying(2) |
division10 | character varying(2) |
statefp10 | character varying(2) |
statens10 | character varying(8) |
geoid10 | character varying(2) |
stusps10 | character varying(2) |
name10 | character varying(100) |
Then I have a table that displays all the urban information. Once again I think I am going to use the name10 variable because it stores the name of all the urban areas.
Table "public.tl_2010_us_uac10"
Column | Type | Modifiers
------------+-----------------------------+-------------------------------------
gid | integer | not null default
uace10 | character varying(5) |
geoid10 | character varying(5) |
name10 | character varying(100) |
The code That I wrote in my sql was
select a.name10 from tl_2010_us_uac10 as a join tl_2010_us_state10 as b where (b.name10 = 'colorado');
but I get this error
LINE 1: ...l_2010_us_uac10 as a join tl_2010_us_state10 as b where (b.n...
gid is a primary key

Answer 1

You must have a join condition for an inner join. Then an order by to meet your sorting requirement.
select a.name10 as urban_area
from tl_2010_us_uac10 as a
join tl_2010_us_state10 as b
on b.gid = a.gid
where b.name10 = 'colorado'
order by a.name10;