Question

我在purchase_order_status表格中有一个名为purchases的列，其中包含Open和Closed作为值。

SELECT *
  FROM purchases
 WHERE purchase_order_status = :status

如果用户将All作为绑定参数传递，如何使用case语句获取具有Open和Closed状态的所有行，如下所示？

in ('Open','Closed')

是否可以在case语句中使用bind变量，例如

case when :status = 'All' then 'Open','Closed'

Answer 1

您可以使用case，但使用普通逻辑运算符更简单，更清晰：

SELECT *
  FROM purchases
 WHERE ((:status = 'All' AND purchase_order_status IN ('Open','Closed'))
    OR purchase_order_status = :status)

使用一些简单的样本数据和一个SQL * Plus绑定变量：

create table purchases (purchase_order_status varchar2(10));

insert into purchases values ('Open');
insert into purchases values ('Closed');
insert into purchases values ('Pending');

var status varchar2(10);

传递'开放'：

exec :status := 'Open';

anonymous block completed

SELECT *
  FROM purchases
 WHERE ((:status = 'All' AND purchase_order_status IN ('Open','Closed'))
    OR purchase_order_status = :status);

PURCHASE_ORDER_STATUS
---------------------
Open

传递'All：

exec :status := 'All';

anonymous block completed

SELECT *
  FROM purchases
 WHERE ((:status = 'All' AND purchase_order_status IN ('Open','Closed'))
    OR purchase_order_status = :status);

PURCHASE_ORDER_STATUS
---------------------
Open                  
Closed

如果您可以保证该列只能保留这两个值，那么您可以将其进一步简化为：

SELECT *
  FROM purchases
 WHERE :status = 'All' OR purchase_order_status = :status;

Answer 2

亚历克斯的回答是更好的IMO，但这里有另一种选择。

declare @test as varchar(10)
set @test = 'ALL'
if(@test='ALL') begin
select * from purchases where purchase_order_status in('Open','Closed')
end
if(@test='OPEN') begin
select * from purchases where purchase_order_status in('Open')
end

就个人而言，我会在生成选择查询的代码中做这种事情（如果有这样的代码）

使用绑定变量的案例声明用法

2 个答案: