如何在PostgreSQL查询中显示行号？

我想显示PostgreSQL查询返回的每个logging的观察编号。

我认为在8.4窗口函数中可以执行这个function。

Answer 1

select row_number() over (order by <field> nulls last) as rownum, * from foo_tbl order by <field> 

如果订单没有必要，这个答案也可能被简化：

 select row_number() over(), * -- notice: no fields are needed from foo_tbl 

Answer 2

对于8.4之前的版本：

 SELECT count(*) rownum, foo.* FROM datatable foo JOIN datatable bar ON (foo.pk_id < bar.pk_id) GROUP BY foo.pk_id, foo.a, foo.b ORDER BY rownum ; -- if there isn't a single unique/primary key field, you can concatenate fields -- Example: ON (foo.a||foo.b||foo.c < bar.a||bar.b||bar.c) 

希望这有助于某人。