pgsql刪除重復記錄

如下：

DELETE 
FROM
    categories a 
WHERE
    ( a.id, a.name, a.parent_id ) IN ( SELECT id, name, parent_id FROM categories GROUP BY id, name, parent_id HAVING count( * ) > 1 ) 
    AND ctid NOT IN ( SELECT min(ctid) FROM categories GROUP BY id, name, parent_id HAVING count( * ) > 1 )

關鍵點：oracle中有內部id為rowid, 在postgresql中有ctid.

參照：oracle rowid and postgresql ctid

參照：SQL 刪除重復記錄，並保留其中一條