POSTGRESQL-返回select查询时出错

这是我的函数，执行此函数时返回错误：

create or replace function country(varchar) 

returns customer(customer_id integer,
                 first_name varchar,                       
                  last_name varchar) as $$


 select customer_id, customer.first_name, customer.last_name 

 from customer 

     inner join address on customer.address_id = address.address_id 
     inner join city on address.city_id = city.city_id 
     inner join country on city.country_id = country.country_id 

where country = '$1';

$$  
language sql;

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返回查询时出错。

使用此解决方案的创建类型：

create type ct as (customer_id integer, first_name varchar, last_name varchar)

现在创建函数

create or replace function country(varchar) 

returns ct as $$

select customer_id, first_name, last_name from customer 
     inner join address on customer.address_id = address.address_id 
     inner join city on address.city_id = city.city_id 
     inner join country on city.country_id = country.country_id    
where country = $1;

$$ language sql;

还是用这个

create or replace function country(varchar) 

returns table(customer_id integer,
                 first_name varchar,                       
                  last_name varchar) as $$ 

 select customer_id, customer.first_name, customer.last_name 

 from customer 

     inner join address on customer.address_id = address.address_id 
     inner join city on address.city_id = city.city_id 
     inner join country on city.country_id = country.country_id 

where country = $1;

$$language sql;

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我认为您有输入错误，您应该使用

where country=$1

，不带单引号。您遇到了什么错误？错误：语法错误位于或接近“整数”行2：返回客户（customer_id integer，谢谢Tim，我删除了单引号，但此错误表明我有语法错误，并指出该整数您能再次帮助我吗？我是postgresERROR的新用户：语法错误在或接近“integer”行2：返回客户（customer_id integer Mureinik，谢谢这是我的错误。谢谢。我使用了您编辑的函数，但现在它返回了。您能再次帮助我吗？DVD租赁=#选择国家（“阿尔及利亚”）；国家---------------------（第1行）这是我得到的结果，你在使用游标吗？你在使用哪一个函数1或2（我在上面写的）我刚刚发现我用游标制作了另一个“国家”函数我把它扔了，然后使用了你的第二个函数它现在工作了。非常感谢你的帮助干杯！