Question

我有这个查询，我想返回零值而不是null值。

    create view ct as
    select userid, coalerse(count(tweets), 0) as nooftweets, coalerse(count(distinct mention), 0) as mention 
from (
    select t.user_id as userid, t.id as tweets, m.mentionedusers_id as mention, row_number() over (partition by m.tweet_id order by m.mentionedusers_id
      ) rn 
    from "tweet_mentUsers" m right join tweet t on m.tweet_id = t.id where text like '@%') a where rn <= 2 group by 1

但是我收到此错误消息：

ERROR:  function coalerse(bigint, integer) does not exist
LINE 2: select userid, coalerse(nooftweets, 0), coalerse(mention, 0)...
                       ^
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.

你有什么想法吗？

Answer 1

我认为COALESCE功能会做你想要的。

create view ct as
select userid, coalesce(count(tweets), 0) as nooftweets, coalesce(count(distinct mention), 0) as mention 
from (
select t.user_id as userid, t.id as tweets, m.mentionedusers_id as mention, row_number() over (partition by m.tweet_id order by m.mentionedusers_id
  ) rn 
from "tweet_mentUsers" m right join tweet t on m.tweet_id = t.id where text like '@%') a where rn <= 2 group by 1

错误：函数coalerse（bigint，整数）不存在

1 个答案: