返回行的简单 PostgreSQL 函数
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Simple PostgreSQL function to return rows
提问by rebnoob
How do I convert a simple select query like select * from customersinto a stored procedure / function in pg?
如何将简单的选择查询（如select * from customerspg）转换为存储过程/函数？
I'm new to Postgres and create function customers() as returns table/setofjust didn't feel right and thus the question here.
我是 Postgres 的新手，create function customers() as returns table/setof只是感觉不对，因此这里的问题。
I understand procs are called "functions" in pg land. Thus create procedurecreate function x() returns setof yreturns a paren'd comma separated row of values which can't be used without further processing (at least that's what I'm seeing in pgAdmin and Ruby/Sequel).
我知道 procs 在 pg land 中被称为“函数”。因此create procedurecreate function x() returns setof y返回一个括号逗号分隔的值行，如果不进一步处理就不能使用（至少这是我在 pgAdmin 和 Ruby/Sequel 中看到的）。
create function x() returns table(...)requires I embed the row definition which I don't want to.
create function x() returns table(...)要求我嵌入我不想嵌入的行定义。
I'm sure there's a reason behind all this but I'm surprised that the most common use case is this tricky.
我确信这一切背后是有原因的，但令我惊讶的是，最常见的用例是如此棘手。
回答by Erwin Brandstetter
The issue is "create function x() returns setof y" returns a paren'd comma separated row values which can't be used without further processing
问题是“创建函数 x() 返回 setof y”返回一个括号逗号分隔的行值，如果不进一步处理就不能使用
Since the function returns a record / row type, you have to call it with
由于该函数返回记录/行类型，因此您必须使用
SELECT * FROM getcustomers();
to decompose the returned row into individual columns.
将返回的行分解为单独的列。
The manual on CREATE FUNCTIONshould be a good starting point. The example section covers this topic.
该手册上创建功能应该是一个很好的起点。示例部分涵盖了这个主题。
回答by Craig Ringer
Untested but should be about right:
未经测试，但应该是正确的：
CREATE OR REPLACE FUNCTION getcustomers() RETURNS SETOF customers AS $$
SELECT * FROM customers;
$$ LANGUAGE sql;
