sql - 其中数组不包含值 Postgres

Question

我正在使用 postgres 来提取一些数据。我有一个数组（类别），我想排除包含“>”的结果

select title, short_url, unnest(categories) as cats, winning_offer_amount
from auctions
where ended_at is not null
and '% > %' NOT IN cats
group by title, short_url, cats, winning_offer_amount

我意识到我的语法完全错误，但试图给出我想要写的东西的想法。结果可能是：

Women's > Shoes
Women's
Men's > Shoes
Men's

我想用'>'排除结果

Answer 1

一个简单的“蛮力”方法是将数组转换为text并检查：

SELECT title, short_url, categories, winning_offer_amount
FROM   auctions
WHERE  ended_at IS NOT NULL
AND    categories::text NOT LIKE '% > %';  -- including blanks?

一个干净优雅unnest()的NOT EXISTS半连接解决方​​案：

SELECT title, short_url, categories, winning_offer_amount
FROM   auctions a
WHERE  ended_at IS NOT NULL
AND    NOT EXISTS (
   SELECT 1
   FROM   unnest(a.categories) AS cat
   WHERE  cat LIKE '% > %'
   );

SQL小提琴。

Answer 2

'>'计算字符出现的次数，cats并且仅在计数等于 0 时才包括记录。

所以，像这样（检查确切的语法）：

select title, short_url, unnest(categories) as cats, winning_offer_amount
from auctions
where ended_at is not null
and (length(cats) - length(replace(cats, '>', '')))=0 
group by title, short_url, cats, winning_offer_amount