Question

我想显示PostgreSQL查询返回的每条记录的观察编号。

我认为在8.4窗口函数中可以执行此功能。

Answer 1

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

如果没有必要订购，也可以简化这个答案：

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。

Answer 3

仅查询不带*的设备，将输出返回的总行数。

select from table_name ...;

如何在PostgreSQL查询中显示行号？

3 个答案: