Question

我试图创建一个查询，它会为所有返回的记录提供一个row_number。我可以为数据库中的所有记录执行此操作。问题是，我需要以某种方式检索内部（WHERE posts.status = 'published'）的WHERE语句的查询的行号。

我的原始查询如下：

SELECT 
    posts.*, 
    row_number() over (ORDER BY posts.score DESC) as position 
FROM posts

但是，在over()中添加where语句会引发语法错误：

SELECT 
    posts.*, 
    row_number() over (
        WHERE posts.status = 'published' 
        ORDER BY posts.score DESC
    ) as position 
FROM posts

Answer 1

SELECT posts.*, row_number() over (ORDER BY posts.score DESC) as position 
FROM posts 
WHERE posts.status = 'published'

Answer 2

不太确定你的目标是什么。也许展示一个预期输出的例子。以下是一种方法示例：

create table posts(id int, score int, status text);
insert into posts values(1, 1, 'x');
insert into posts values(2, 2, 'published');
insert into posts values(3, 3, 'x');
insert into posts values(4, 4, 'x');

SELECT x.id, x.score, x.status
      ,CASE WHEN x.status = 'published' THEN null ELSE x.position END
  FROM (SELECT posts.*,
               row_number() OVER (ORDER BY posts.score DESC)
               -SUM(CASE WHEN status = 'published' THEN 1 ELSE 0 END)
                  OVER (ORDER BY posts.score DESC) as position
          FROM posts
       ) x

结果：

4  4  x         1
3  3  x         2
2  2  published
1  1  x         3

在OVER（）中使用WHERE语句

2 个答案: