以下主要介绍PostgreSQL函数/存储过程返回数据集，或者也叫结果集的示例。  背景： PostgreSQL里面没有存储过程，只有函数，其他数据库里的这两个对象在PG里都叫函数。 函数由函数头，体和语言所组成，函数头主要是函数的定义，变量的定义等，函数体主要是函数的实现，函数的语言是指该函数实现的方式，目前内置的有c,plpgsql,sql和internal,可以通过pg_language来查看当前DB支持的语言，也可以通过扩展来支持python等  函数返回值一般是类型，比如return int,varchar，返回结果集时就需要setof来表示。  **一、数据准备** ~~~ create table department(id int primary key, name text); create table employee(id int primary key, name text, salary int, departmentid int references department); insert into department values (1, 'Management'),(2, 'IT'),(3, 'BOSS'); insert into employee values (1, 'kenyon', 30000, 1); insert into employee values (2, 'francs', 50000, 1); insert into employee values (3, 'digoal', 60000, 2); insert into employee values (4, 'narutu', 120000, 3); ~~~ **二、例子**  1.sql一例 ~~~ create or replace function f_get_employee() returns setof employee as $$ select * from employee; $$ language 'sql'; ~~~ 等同的另一个效果(Query) ~~~ create or replace function f_get_employee_query() returns setof employee as $$ begin return query select * from employee; end; $$ language plpgsql; ~~~ 查询图解如下 ~~~ postgres=# select * from f_get_employee(); id | name | salary | departmentid ----+--------+--------+-------------- 1 | kenyon | 30000 | 1 2 | francs | 50000 | 1 3 | digoal | 60000 | 2 4 | narutu | 120000 | 3 (4 rows) ~~~ 查询出来的函数还可以像普通的表一样按条件查询 ,但如果查询的方式不一样，则结果也不一样，以下查询方式将会得到类似数组的效果 ~~~ postgres=# select f_get_employee(); f_get_employee --------------------- (1,kenyon,30000,1) (2,francs,50000,1) (3,digoal,60000,2) (4,narutu,120000,3) (4 rows) ~~~ 因为返回的结果集类似一个表的数据集，PostgreSQL还支持对该函数执行结果进行条件判断并过滤 ~~~ postgres=# select * from f_get_employee() where id >3; id | name | salary | departmentid ----+--------+--------+-------------- 4 | narutu | 120000 | 3 (1 row) ~~~ 上面的例子相对简单，如果要返回不是表结构的数据集该怎么办呢？看下面  2.返回指定结果集  a.用新建type来构造返回的结果集  --新建的type在有些图形化工具界面中可能看不到， 要查找的话可以通过select * from pg_class where relkind='c'去查，c表示composite type ~~~ create type dept_salary as (departmentid int, totalsalary int); create or replace function f_dept_salary() returns setof dept_salary as $$ declare rec dept_salary%rowtype; begin for rec in select departmentid, sum(salary) as totalsalary from f_get_employee() group by departmentid loop return next rec; end loop; return; end; $$ language 'plpgsql'; ~~~ b.用Out传出的方式 ~~~ create or replace function f_dept_salary_out(out o_dept text,out o_salary text) returns setof record as $$ declare v_rec record; begin for v_rec in select departmentid as dept_id, sum(salary) as total_salary from f_get_employee() group by departmentid loop o_dept:=v_rec.dept_id; o_salary:=v_rec.total_salary; return next; end loop; end; $$ language plpgsql; ~~~ 执行结果: ~~~ postgres=# select * from f_dept_salary(); departmentid | totalsalary --------------+------------- 1 | 80000 3 | 120000 2 | 60000 (3 rows) postgres=# select * from f_dept_salary_out(); o_dept | o_salary --------+---------- 1 | 80000 3 | 120000 2 | 60000 (3 rows) ~~~ c.根据执行函数变量不同返回不同数据集 ~~~ create or replace function f_get_rows(text) returns setof record as $$ declare rec record; begin for rec in EXECUTE 'select * from ' || $1 loop return next rec; end loop; return; end $$ language 'plpgsql'; ~~~ 执行结果： ~~~ postgres=# select * from f_get_rows('department') as dept(deptid int, deptname text); deptid | deptname --------+------------ 1 | Management 2 | IT 3 | BOSS (3 rows) postgres=# select * from f_get_rows('employee') as employee(employee_id int, employee_name text,employee_salary int,dept_id int); employee_id | employee_name | employee_salary | dept_id -------------+---------------+-----------------+--------- 1 | kenyon | 30000 | 1 2 | francs | 50000 | 1 3 | digoal | 60000 | 2 4 | narutu | 120000 | 3 (4 rows) ~~~ 这样同一个函数就可以返回不同的结果集了，很灵活。  参考：http://bbs.pgsqldb.com/client/post_show.php?zt_auto_bh=53950