Question

嗨，我需要根据where子句中满足的条件对行进行排名。所以我写了查询

select 1 as priority, usr_fname, usr_lname from core_users where usr_fname = 'John' and usr_lname = 'smith' and suburb = '0162'
union
select 2 as priority, usr_fname, usr_lname from core_users where usr_fname = 'John' and usr_lname = 'smith' and usr_title = 'Mr' 
union
select 3 as priority, usr_fname, usr_lname from core_users where usr_fname = 'John' and usr_lname = 'smith'

现在我的TL坚持我可以在这里使用sql rank（）/ row_number（）。有人可以指导吗？

Answer 1

如果您确实使用row_number()，则可以获取3个以上的值：

select usr_fname, usr_lname,
       row_number() over (case when suburb = '0162' then 1
                               when usr_title = 'Mr' then 2
                               else 3
                          end) as priority
from core_users
where usr_fname = 'John' and usr_lname = 'smith' ;

您可以使用dense_rank()而不是row_number()获得同等的优先级。但是，如果数据中没有全部显示三个组，则数字将为“ 1”或“ 1”和“ 2”。

但是，更简单的版本仅使用case表达式即可满足您的要求：

select usr_fname, usr_lname,
       (case when suburb = '0162' then 1
             when usr_title = 'Mr' then 2
             else 3
        end) as priority
from core_users
where usr_fname = 'John' and usr_lname = 'smith' ;

您的版本多次返回同一行-针对它匹配的每个优先级一次。这只会返回每行一次，我猜这是您的实际意图。

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