这是我的表格:
<块引用>创建表国家( country_id number(5) 主键, 国家 varchar2(36) );
create table city(
city_id number(5) primary key,
country_id number(5) constraint city_country_fk references country(country_id) NOT NULL,
city varchar2(36)
);
SQL> desc airportdemodata;
Name Null? Type
----------------------------------------- -------- ----------------------------
AIRPORT_ID NOT NULL NUMBER(5)
IATA_CODE VARCHAR2(3)
CITY VARCHAR2(36)
COUNTRY VARCHAR2(36)
AIRPORT VARCHAR2(58)
我将机场演示数据中的国家/地区插入到国家/地区表中,如下所示:
INSERT INTO country (country)
SELECT unique(country) from airportdemodata;
效果很好。
现在我试图通过将 airportdemodata.country 与 country.country 匹配来将 airportdemodata.city 复制到 city.city(country_id,city)。我试过这样:
SQL> SELECT a.unique(city), b.country_id FROM airportdemodata a, country b where a.country=b.country;
SELECT a.unique(city), b.country_id FROM airportdemodata a, country b where a.country=b.country
*
ERROR at line 1:
ORA-01747: invalid user.table.column, table.column, or column specification
答案 0 :(得分:0)
对;发明你自己的语法通常会导致你所经历的结果。您是要使用 distinct
吗?
SELECT DISTINCT a.city,
b.country_id
FROM airportdemodata a
JOIN country b ON a.country = b.country;