我正在使用 PostgreSQL 9.1 版并查看 Postgres docs ,我知道可以执行以下操作:
SELECT salary, sum(salary) OVER (ORDER BY salary) FROM empsalary;
这适用于我的查询。
现在我需要能够在 OVER (ORDER BY ...)
中指定别名而不是列名?
我试过这个:
编辑:我之前忘记将 rank()
添加到此查询中:
SELECT salary, <complex expression> as result, rank() OVER (ORDER BY result) FROM empsalary;
我收到一条错误消息,提示 column "result"does not exist.
是否可以在这里指定别名而不是列名?我是否遗漏了一些特殊的语法?
编辑:
我正在使用 Hibernate,并为窗口函数使用了一些 native SQL。生成和执行的完整 SQL 如下:
select
rank() OVER (ORDER BY deltahdlcOverruns DESC) as rank,
this_.deviceNo as y1_,
(SELECT _dev_.hdlcOverruns FROM abstractperformancestatistic _abs_
INNER JOIN enddevicestatistic _dev_ ON _dev_.id = _abs_.id
INNER JOIN linkstatistic _link_ ON _link_.id = _dev_.linkStatistic_id
INNER JOIN iptstatistic _ipt_ ON _ipt_.id = _link_.iptStat_id
WHERE this_.deviceNo=_dev_.deviceNo AND _abs_.dateTime <= '3910-06-07 00:00:00.0'
ORDER BY _abs_.dateTime DESC LIMIT 1
)
-
(SELECT _dev_.hdlcOverruns FROM abstractperformancestatistic _abs_
INNER JOIN enddevicestatistic _dev_ ON _dev_.id = _abs_.id
INNER JOIN linkstatistic _link_ ON _link_.id = _dev_.linkStatistic_id
INNER JOIN iptstatistic _ipt_ ON _ipt_.id = _link_.iptStat_id
WHERE this_.deviceNo=_dev_.deviceNo AND _abs_.dateTime >= '3870-06-01 00:00:00.0'
ORDER BY _abs_.dateTime LIMIT 1
)
AS deltahdlcOverruns from EndDeviceStatistic this_
inner join AbstractPerformanceStatistic this_1_ on this_.id=this_1_.id
inner join AbstractEntity this_2_ on this_.id=this_2_.id
left outer join RawEndDeviceStatistic this_3_ on this_.id=this_3_.id
left outer join LinkStatistic l2_ on this_.linkStatistic_id=l2_.id
left outer join AbstractPerformanceStatistic l2_1_ on l2_.id=l2_1_.id
left outer join AbstractEntity l2_2_ on l2_.id=l2_2_.id
left outer join RawLinkStatistic l2_3_ on l2_.id=l2_3_.id
left outer join IPTStatistic i1_ on l2_.iptStat_id=i1_.id
left outer join AbstractPerformanceStatistic i1_1_ on i1_.id=i1_1_.id
left outer join AbstractEntity i1_2_ on i1_.id=i1_2_.id
left outer join RawIPTStatistic i1_3_ on i1_.id=i1_3_.id
where this_1_.dateTime between ? and ?
group by this_.deviceNo limit ?
最佳答案
将别名放在 OVER
子句之后:
SELECT salary
, sum(salary) OVER (ORDER BY salary) <b>AS my_alias</b>
FROM empsalary;
问题更新后编辑
您不能在 SELECT
的同一级别引用列别名(“输出列”)。您需要一个子选择或一个 CTE为了这。喜欢:
SELECT id, result, rank() OVER (ORDER BY result) AS rnk
FROM (
SELECT id, <complex expression> AS result
FROM tbl
WHERE <some condition>
GROUP BY id
) sub;
对于您的查询:
SELECT rank() OVER (ORDER BY deltahdlcOverruns) AS rnk
, y1_
, deltahdlcOverruns
FROM (
SELECT this_.deviceNo as y1_
, (SELECT _dev_.hdlcOverruns FROM abstractperformancestatistic _abs_
JOIN enddevicestatistic _dev_ USING (id)
JOIN linkstatistic _link_ ON _link_.id = _dev_.linkStatistic_id
JOIN iptstatistic _ipt_ ON _ipt_.id = _link_.iptStat_id
WHERE this_.deviceNo=_dev_.deviceNo
AND _abs_.dateTime <= '3910-06-07 00:00:00.0'
ORDER BY _abs_.dateTime DESC
LIMIT 1
)
-
(SELECT _dev_.hdlcOverruns FROM abstractperformancestatistic _abs_
JOIN enddevicestatistic _dev_ USING (id)
JOIN linkstatistic _link_ ON _link_.id = _dev_.linkStatistic_id
JOIN iptstatistic _ipt_ ON _ipt_.id = _link_.iptStat_id
WHERE this_.deviceNo=_dev_.deviceNo
AND _abs_.dateTime >= '3870-06-01 00:00:00.0'
ORDER BY _abs_.dateTime
LIMIT 1
) AS deltahdlcOverruns
FROM EndDeviceStatistic this_
JOIN AbstractPerformanceStatistic this_1_ USING (id)
JOIN AbstractEntity this_2_ USING (id)
LEFT JOIN RawEndDeviceStatistic this_3_ USING (id)
LEFT JOIN LinkStatistic l2_ ON this_.linkStatistic_id = l2_.id
LEFT JOIN AbstractPerformanceStatistic l2_1_ ON l2_.id = l2_1_.id
LEFT JOIN AbstractEntity l2_2_ ON l2_.id = l2_2_.id
LEFT JOIN RawLinkStatistic l2_3_ ON l2_.id = l2_3_.id
LEFT JOIN IPTStatistic i1_ ON l2_.iptStat_id = i1_.id
LEFT JOIN AbstractPerformanceStatistic i1_1_ ON i1_.id = i1_1_.id
LEFT JOIN AbstractEntity i1_2_ ON i1_.id = i1_2_.id
LEFT JOIN RawIPTStatistic i1_3_ ON i1_.id = i1_3_.id
WHERE this_1_.dateTime between ? and ?
GROUP BY this_.deviceNo
LIMIT ?
) x;
我做了一些额外的语法简化。
关于sql - 在 PostgreSQL 的查询中的窗口函数中使用别名,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/7915303/