Question

我正在Codewars.com上进行SQL挑战。到目前为止，一切都很好。

我要解决的挑战是https://www.codewars.com/kata/calculating-month-over-month-percentage-growth-rate/train/sql

我的SQL看起来像：

select date_trunc('month', created_at)::date as date, 
  count(distinct created_at) as count, 
  100 * (count(*) - lag(count(*), 1) over (order by date)) / lag(count(*), 1) over (order by date)) || '%' as growth
from posts
group by date
order by date asc

但是，服务器不断向我退回PG::SyntaxError: ERROR: subquery in FROM must have an alias

我不是Postgres的专家，但我知道我对任务的期望有日期，计数和增长的别名。

我还想念什么？

欢迎任何帮助。

Answer 1

没关系，我发现了一个问题。我在这一行中有一个额外的括号：

100 * (count(*) - lag(count(*), 1) over (order by date)) / lag(count(*), 1) over (order by date)) || '%' as growth

应该是：

100 * (count(*) - lag(count(*), 1) over (order by date)) / lag(count(*), 1) over (order by date) || '%' as growth

Codewars Postgres挑战pg :: syntaxerror

1 个答案: