Question

我正在创建SQL查询以从表中返回信息，但我特别遇到问题。我想要归还科罗拉多州的所有城市地区。查询的实际定义是

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)

我使用的表是tl_2010_us_state10（它存储状态的信息）。我想我将在这个表中使用name10变量，因为它具有状态的所有名称。

    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)      |

然后我有一张显示所有城市信息的表格。我再一次认为我将使用name10变量，因为它存储了所有城市区域的名称。

                                      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)      |

我在sql中编写的代码是

 select a.name10 from tl_2010_us_uac10 as a join tl_2010_us_state10 as b where (b.name10 = 'colorado');

但我收到此错误

LINE 1: ...l_2010_us_uac10 as a join tl_2010_us_state10 as b where (b.n...

gid是主键

Answer 1

您必须具有内部联接的连接条件。然后订购以满足您的分拣要求。

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;

创建sql语句以从表中返回信息

1 个答案: