Postgres的功能与选择

我想显示的功能如下：Postgres的功能与选择

select LoanId, BookId ,(OutDate-InDate)*0.3 as money, OutDate-InDate days 
from loans 
where (OutDate-InDate)> 30 and OutDate::varchar(4)='2000';

作为输入只有一年，作为输出应该返回选择。我试过make功能，但它不起作用。任何想法？

来源

2016-01-08 R0ck99

请分享您的代码，并解释到底是什么没有在那里工作。 – Mureinik

请阅读以下内容并在问题中添加更多信息，以便我们提供帮助！ https://stackoverflow.com/help/mcve – Ross

我试图读你的思想，所以我可以回答你的问题....但它没有奏效。任何想法？ –

我有一个表像下面

create table loan(loanid int,bookid int,outdate date,indate date);

像这样

insert into loan values(1,2,'01-12-2015','01-10-2015'),(1,2,'01-01-2016','08-01-2016');

一些数据，我用下面的select查询

select loanid,bookid,(outdate-indate)*0.3 as "money",outdate-indate as "days" 
from loan 
where (OutDate-InDate)> 30 and extract(year from outdate)='2015' 

loanid bookid money days 
------ ------ ----- ---- 
1  2  18.3 61

现在我有一个函数做的工作是

create or replace function FN_LOAN_DET(in_year text) 
returns table (loanid int,bookid int,money numeric,days int) 
as 
$$ 
select loanid,bookid,(outdate-indate)*0.3 as "money",outdate-indate as "days" 
from loan 
where (OutDate-InDate)> 30 and extract(year from outdate)=$1 
$$ 
language sql

当我打电话select * from FN_LOAN_DET('2015')我会得到

loanid bookid money days 
------ ------ ----- ---- 
1  2  18.3 61

来源

2016-01-08 05:29:43

Postgres的功能与选择

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