PostgresSQL查询
如果我有如下表格:PostgresSQL查询,sql,postgresql,Sql,Postgresql,如果我有如下表格: Meter Serial Date | Reading A 2017-01-01 10 B 2017-02-10 20 A 2017-03-05 20 B 2017-05-01 100 A 2017-06-01 300 Meter | Date Start | S
Meter Serial Date | Reading
A 2017-01-01 10
B 2017-02-10 20
A 2017-03-05 20
B 2017-05-01 100
A 2017-06-01 300
Meter | Date Start | Start Reading | Date End | End Reading
A 2017-01-01 10 2017-03-05 20
B 2017-02-10 20 2017-05-01 30
A 2017-03-05 20 2017-06-01 300
是否可以获得如下显示的查询:
Meter Serial Date | Reading
A 2017-01-01 10
B 2017-02-10 20
A 2017-03-05 20
B 2017-05-01 100
A 2017-06-01 300
Meter | Date Start | Start Reading | Date End | End Reading
A 2017-01-01 10 2017-03-05 20
B 2017-02-10 20 2017-05-01 30
A 2017-03-05 20 2017-06-01 300
注意:读数并非每天都有。但它们在给定的一天是唯一的(例如,您不能在同一天有两个读数)
这是我正在处理的当前查询:
with tbl as (select row_number() over(order by read_date) as rn, meter_serial, meter_channel, total_meter_read, read_date
from meter_reading_total)
select l.meter_serial, l.read_date, l.total_meter_read, r.read_date, r.total_meter_read
from tbl as l
left outer join
tbl as r
on r.rn = l.rn + 1
and r.meter_serial = l.meter_serial
and r.meter_channel = l.meter_channel
如果希望按日期自动加入,则按1天间隔自动加入。否则,如果需要按记录顺序将连接条件更改为r.id=l.id+1
如果您的表没有id列,则可以使用rownumber函数和cte
作为
将order by dt
更改为order by 1
将在日期范围内加入表,即使它们未排序
如果希望按日期自动加入,则按1天间隔自动加入。否则,如果需要按记录顺序将连接条件更改为r.id=l.id+1
如果您的表没有id列,则可以使用rownumber函数和cte
作为
将order by dt
更改为order by 1
将在日期范围内加入表格,即使这些日期范围未排序。此选项应适用于:
SELECT sub1.meter, sub1.date as date_start, sub1.reading as start_reading, sub2.meter, sub2.date as date_end, sub2.reading as end_reading
FROM
(SELECT ROW_NUMBER() OVER(ORDER BY meter, date ASC) AS row, t.*
FROM t) sub1
INNER JOIN
(SELECT ROW_NUMBER() OVER(ORDER BY meter, date ASC) AS row, t.*
FROM t) sub2 ON sub1.row = sub2.row -1
AND sub1.meter = sub2.meter
在这里试试:这个应该可以:
SELECT sub1.meter, sub1.date as date_start, sub1.reading as start_reading, sub2.meter, sub2.date as date_end, sub2.reading as end_reading
FROM
(SELECT ROW_NUMBER() OVER(ORDER BY meter, date ASC) AS row, t.*
FROM t) sub1
INNER JOIN
(SELECT ROW_NUMBER() OVER(ORDER BY meter, date ASC) AS row, t.*
FROM t) sub2 ON sub1.row = sub2.row -1
AND sub1.meter = sub2.meter
请在此处尝试:窗口功能FTW
SELECT
meter_serial,
meter_date AS start_date,
readings AS start_reads,
lead(meter_date) OVER read_wdw AS end_date,
lead(readings) OVER read_wdw AS end_reads
FROM read_meter
WINDOW read_wdw AS (
PARTITION BY meter_serial
ORDER BY meter_date ASC
)
ORDER BY start_date ASC
下面是本例的示例。窗口功能FTW
SELECT
meter_serial,
meter_date AS start_date,
readings AS start_reads,
lead(meter_date) OVER read_wdw AS end_date,
lead(readings) OVER read_wdw AS end_reads
FROM read_meter
WINDOW read_wdw AS (
PARTITION BY meter_serial
ORDER BY meter_date ASC
)
ORDER BY start_date ASC
以下是本例的示例。该表的日期范围不相等。看看第四个读数。我想我面临的问题是,我在同一张表中有多个仪表,我需要按仪表排序。在问题的底部,我将发布我正在运行的实际查询将
row\u number()over(按读取日期排序)
更改为row\u number()over(按米划分\u按读取日期排序)
在您的查询表中该表的日期范围不相等。看看第四个读数。我想我面临的问题是,我在同一张表中有多个仪表,我需要按仪表排序。在问题的底部,我将发布我正在运行的实际查询,将查询名结果中的row\u number()改为row\u number()(按读取日期排序)
。我只在两天相隔只有一天的情况下得到结果,但我需要一个范围。我想这是因为我需要更多的信息。e、 g.同一表格中的不同仪表。已经更新了问题…相同的结果。我只在两天相隔只有一天的情况下得到结果,但我需要一个范围。我想这是因为我需要更多的信息。e、 g.同一表格中的不同仪表。已经更新了问题。。。