时间戳

首页 > 解决方案 > 根据条件下订单

mysql - 根据条件下订单

问题描述

我有一个查询：

SELECT * FROM Cars WHERE (cars.mark = "Audi" and cars.model = "a4" and cars.year = 2008) or 
             (cars.mark = "Audi" and cars.model <> "a4" and cars.year = 2008) or  
             (cars.mark <> "Audi" and cars.model <> "a4" and cars.year = 2008 )

我怎样才能按条件订购。第一个结果：cars.mark = "Audi" and cars.model = "a4" and cars.year = 2008下一个结果：(cars.mark = "Audi" and cars.model <> "a4" and cars.year = 2008)和第三个 : (cars.mark <> "Audi" and cars.model <> "a4" and cars.year = 2008 )。

我不能使用联合查询，因为它是 Symfony 项目，它不支持联合。谢谢

标签： mysqlsymfonydoctrine-orm

解决方案

不确定您的 where 条件是否有用，基本上它说给我所有标记一个 2008 年的模型，我很确定该模型在所有标记中都是唯一的。至于结果的排序，您可以有条件地排序。

drop table if exists t;
create table t
(mark varchar(4) , model varchar(4), year int);

insert into t values
('audi','a3',2008),
('ford','st',2008),
('audi','a4',2008),
('gm','junk',2008),
('gm','junk',2009),
('ford','xx',2008);


SELECT * FROM t 
WHERE  year = 2008
order by 
case when t.mark = "Audi" and t.model = "a4"  then 1 
     when t.mark = "Audi" and t.model <> "a4"  then 2 
     when t.mark <> "Audi" and t.model <> "a4" then 3
     else 4
     end ,
mark desc;

+------+-------+------+
| mark | model | year |
+------+-------+------+
| audi | a4    | 2008 |
| audi | a3    | 2008 |
| gm   | junk  | 2008 |
| ford | st    | 2008 |
| ford | xx    | 2008 |
+------+-------+------+

推荐阅读