PostgreSQL DELETE FROM (SELECT * FROM table 仅获取前 10 行)

Question

如何在 postgreSQL 中只删除几行？我想获取 10 行以在子查询中删除。

我的table

Answer 1

您需要根据您的要求使用 where 条件，如下所示：

delete from mytable where id in(1,2,3,4,5,6,7,8,9,10)

或

delete from mytable where id in(select id from mytable where someconditon)

或者如果你想使用 ctid 删除前 10 名，你可以这样尝试：

DELETE FROM mytable 
WHERE ctid IN (
    SELECT ctid
    FROM mytable 
    GROUP BY s.serialId, s.valuetimestamp
    ORDER BY s.serialId
    LIMIT 10
)

如果您想从 table 中删除重复项，请尝试以下操作：

DELETE FROM mytable
 WHERE ctid NOT IN
  (SELECT MAX(s.ctid)
    FROM table s
    GROUP BY s.serialId, s.valuetimestamp);

Answer 2

如果您的 table 中有一些唯一标识符（序列号，我们称它为 "id"），那么只需制作如下内容：

DELETE FROM table WHERE table.id IN (SELECT table.id FROM table WHERE *whatever*)

添加或不添加 "LIMIT 0,10"

PostgreSQL DELETE FROM (SELECT * FROM table 仅获取前 10 行)

PostgreSQL DELETE FROM (SELECT * FROM table FETCH FIRST 10 ROWS ONLY)

postgresql

subquery

sql-delete