Oracle vs PostgreSQL Develop（23） - PL(pg)sql(参数声明)

来源：这里教程网时间：2026-03-14 19:44:21 作者：

Oracle和PostgreSQL都提供了内置的编程语言（PL/SQL vs PL/pgSQL），在输入输出参数的声明上有较大的不同，如输入参数中存在inout/out参数，Oracle的函数可以有返回值，但PG不允许有返回值，只能通过参数返回。
**Oracle**
创建函数
```
TEST-orcl@DESKTOP-V430TU3>CREATE or replace FUNCTION sf_testparameter(p1 varchar2,p2 int,p3 varchar2,p4  in out int)
  2  RETURN varchar2
  3  is
  4  begin
  5    p4 := 1;
  6    return 'test';
  7  end;
  8  /
Function created.
```
执行
```
TEST-orcl@DESKTOP-V430TU3>select sf_testparameter(null,null,null,:p4) from dual;
select sf_testparameter(null,null,null,:p4) from dual
       *
ERROR at line 1:
ORA-06572: Function SF_TESTPARAMETER has out arguments
```
不能在SQL中执行，但可以在PL/SQL中执行
```
TEST-orcl@DESKTOP-V430TU3>set serveroutput on
TEST-orcl@DESKTOP-V430TU3>declare
  2    p4 number;
  3    ret varchar2(100);
  4  begin
  5    ret := sf_testparameter(null,null,null,p4);
  6    dbms_output.put_line('p4 = '||p4||',ret='||ret);
  7  end;
  8  /
p4 = 1,ret=test
```
**PostgreSQL**
创建函数，参数中存在inout类型的参数，返回值必须与该参数类型一样，而且return不能返回实际值。
```
[local:/data/run/pg12]:5120 pg12@testdb=# CREATE or replace FUNCTION sf_testparameter(p1 text,p2 int,p3 text,inout p4 int)
pg12@testdb-#   RETURNS text 
pg12@testdb-#   AS $$
pg12@testdb$# begin
pg12@testdb$#   return 'test';
pg12@testdb$# end;
pg12@testdb$# $$ LANGUAGE 'plpgsql';
ERROR:  function result type must be integer because of OUT parameters
[local:/data/run/pg12]:5120 pg12@testdb=# 
[local:/data/run/pg12]:5120 pg12@testdb=# drop function sf_testparameter;
ERROR:  could not find a function named "sf_testparameter"
[local:/data/run/pg12]:5120 pg12@testdb=# CREATE or replace FUNCTION sf_testparameter(p1 text,p2 int,p3 text,inout p4 int)
pg12@testdb-#   RETURNS int 
pg12@testdb-#   AS $$
pg12@testdb$# begin
pg12@testdb$#   return 1;
pg12@testdb$# end;
pg12@testdb$# $$ LANGUAGE 'plpgsql';
ERROR:  RETURN cannot have a parameter in function with OUT parameters
LINE 5:   return 1;
                 ^
[local:/data/run/pg12]:5120 pg12@testdb=# 
[local:/data/run/pg12]:5120 pg12@testdb=# CREATE or replace FUNCTION sf_testparameter(p1 text,p2 int,p3 text,inout p4 int)
pg12@testdb-#   RETURNS int 
pg12@testdb-#   AS $$
pg12@testdb$# begin
pg12@testdb$#   return;
pg12@testdb$# end;
pg12@testdb$# $$ LANGUAGE 'plpgsql';
CREATE FUNCTION
[local:/data/run/pg12]:5120 pg12@testdb=# select sf_testparameter(null,null,null,null);
 sf_testparameter 
------------------
                 
(1 row)
[local:/data/run/pg12]:5120 pg12@testdb=# 
```
如参数中有多个out参数，则要求返回record类型
```
[local:/data/run/pg12]:5120 pg12@testdb=# drop function sf_testparameter;
ION sf_testparameter(p1 text,p2 int,p3 text,inout p4 int,out p5 text)
  RETURNS record
  AS $$
begin
  return;
end;
$$ LANGUAGE 'plpgsql';
\df sf_testparameter
select sf_testparameter(null,null,null,null,null);
select sf_testparameter(null,null,null,null);
DROP FUNCTION
[local:/data/run/pg12]:5120 pg12@testdb=# CREATE or replace FUNCTION sf_testparameter(p1 text,p2 int,p3 text,inout p4 int,out p5 text)
pg12@testdb-#   RETURNS text 
pg12@testdb-#   AS $$
pg12@testdb$# begin
pg12@testdb$#   return 'test';
pg12@testdb$# end;
pg12@testdb$# $$ LANGUAGE 'plpgsql';
ERROR:  function result type must be record because of OUT parameters
[local:/data/run/pg12]:5120 pg12@testdb=# 
[local:/data/run/pg12]:5120 pg12@testdb=# drop function sf_testparameter;
ERROR:  could not find a function named "sf_testparameter"
[local:/data/run/pg12]:5120 pg12@testdb=# CREATE or replace FUNCTION sf_testparameter(p1 text,p2 int,p3 text,inout p4 int,out p5 text)
pg12@testdb-#   RETURNS record
pg12@testdb-#   AS $$
pg12@testdb$# begin
pg12@testdb$#   return;
pg12@testdb$# end;
pg12@testdb$# $$ LANGUAGE 'plpgsql';
CREATE FUNCTION
[local:/data/run/pg12]:5120 pg12@testdb=# 
[local:/data/run/pg12]:5120 pg12@testdb=# \df sf_testparameter
List of functions
-[ RECORD 1 ]-------+------------------------------------------------------------
Schema              | public
Name                | sf_testparameter
Result data type    | record
Argument data types | p1 text, p2 integer, p3 text, INOUT p4 integer, OUT p5 text
Type                | func
[local:/data/run/pg12]:5120 pg12@testdb=# 
[local:/data/run/pg12]:5120 pg12@testdb=# select sf_testparameter(null,null,null,null,null);
ERROR:  function sf_testparameter(unknown, unknown, unknown, unknown, unknown) does not exist
LINE 1: select sf_testparameter(null,null,null,null,null);
               ^
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
[local:/data/run/pg12]:5120 pg12@testdb=# select sf_testparameter(null,null,null,null);
 sf_testparameter 
------------------
 (,)
(1 row)
[local:/data/run/pg12]:5120 pg12@testdb=# 
```
不管有多少个out参数，都归为return参数，在调用时不需要作为参数输入，难怪PG要求返回record类型。
```
[local:/data/run/pg12]:5120 pg12@testdb=# drop function sf_testparameter;
DROP FUNCTION
[local:/data/run/pg12]:5120 pg12@testdb=# CREATE or replace FUNCTION sf_testparameter(p1 text,p2 int,p3 text,inout p4 int,out p5 text,out p6 text)
pg12@testdb-#   RETURNS record
pg12@testdb-#   AS $$
pg12@testdb$# begin
pg12@testdb$#   return;
pg12@testdb$# end;
pg12@testdb$# $$ LANGUAGE 'plpgsql';
CREATE FUNCTION
[local:/data/run/pg12]:5120 pg12@testdb=# select sf_testparameter(null,null,null,null);
 sf_testparameter 
------------------
 (,,)
(1 row)
[local:/data/run/pg12]:5120 pg12@testdb=# 
[local:/data/run/pg12]:5120 pg12@testdb=#

```
**参考资料**
N/A