如何通过sql语句的where子句中的匹配参数数来订购表？

Question

我正在编写sql来通过许多参数搜索数据库.我如何按照与where子句中的大多数参数匹配的项来排序结果集.例如:

SELECT * 
FROM users 
WHERE username = 'eitan' 
OR email = 'eitan@eitan.com' 
OR company = 'eitan'


Username   |  email                |   company

1) eitan   |     blah@blah.com     |     blah

2) eitan   |     eitan@eitan.com   |    eitan

3) eitan   |    eitan@eitan.com    |     blah

应订购如下:

2,3,1.

谢谢.(ps查询不是那么容易,在WHERE中有很多连接和很多OR)

埃坦

Answer 1

如果MySQL:

SELECT * FROM users 
ORDER BY 
    (username = 'eitan') 
    + (email = 'eitan@eitan.com') 
    + (company = 'eitan') 
    DESC

如果PostgreSQL:

SELECT * FROM users 
ORDER BY 
    (username = 'eitan')::int 
    + (email = 'eitan@eitan.com')::int 
    + (company = 'eitan')::int 
    DESC

如果是Sql Server:

SELECT * FROM users 
ORDER BY 
    case when username = 'eitan' then 1 else 0 end
    + case when email = 'eitan@eitan.com' then 1 else 0 end
    + case when company = 'eitan' then 1 else 0 end
    DESC