其中数组不包含值Postgres

Question

我使用postgres来提取一些数据。我有一个数组（类别），我想要排除包含＆＃39; ＆GT; ＆＃39;

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

我意识到我的语法是完全错误的，但试图让我知道我想要写什么。结果可能是：

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

我想用＆＃39;排除结果。 ＆GT; ＆＃39;

Answer 1

一种简单的“强力”方法是将数组强制转换为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?

unnest()半合并中 NOT EXISTS的简洁优雅解决方案：

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 Fiddle.

Answer 2

计算'>'字符在cats中出现的次数，如果计数等于零，则仅包括记录。

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