sql - 如何使用 Distinct ON 计数

Question

我有这个查询已经有效，我需要为此编写计数查询(需要分页)，并且我在使用带有 DISTINCT ON 的计数时遇到问题，任何人都知道正确的语法和使用它的方法，我已经用谷歌搜索但没有能够找到任何带有 DISTINCT ON 的计数查询

结果我期望这个查询的总行数已经有效

select DISTINCT on (csd.team_contest_id)
        c.id as contestId
            from contest as c
            left join company_sponsor_team as csd on csd.contest_id = c.id
            left join sponsor as s on s.id = c.sponsor_id
            left join team as d on d.id = c.team_id
            left join player as m on c.creator_id = m.id
            WHERE c.id = c.id 
            AND ((c.team_id is not null and c.sponsor_id is null and lower(d.name) LIKE LOWER(CONCAT('%TAN%')))
            OR (c.team_id is not null and c.sponsor_id is not null and lower(s.name) LIKE LOWER(CONCAT('%TAN%')))
            OR (c.team_id is null and lower(s.name) LIKE LOWER(CONCAT('%TAN%')))) AND (CURRENT_DATE < c.archive_date)

Answer 1

如果要统计行数，使用子查询:

select count(*)
from ( <your query here> ) x;

如果你厌恶子查询，你总是可以这样做:

select count(distinct csd.team_contest_id)
from . . .  <the rest of your query here>;

假设 csd.team_contest_id 不是 NULL，这将返回相同的值。