Postgresql - 如何使用循环（或在 r 中应用）来减小 r 脚本的大小
Postgresql - how to make use of loop (or apply in r) to decrease the r-script size
我的数据库中有两个表。两个表中的列及其数据类型如下所示。假设两个表都存储 3 台机器的数据。每台机器都有两个 s_id，通过使用它们，我将 select 特定机器所需的数据。
每台机器的s_id是
m1 59,07
m2 60,92
m3 95,109
Table "public.table_a"
Column | Type | Modifiers | Storage | Stats target | Description
--------------+-----------------------------+-----------+---------+--------------+-------------
ettime | timestamp without time zone | | plain | |
sn | numeric | | main | |
s_id1 | numeric | | main | |
e_id1 | numeric | | main | |
Indexes:
"table_a_sn_key" UNIQUE CONSTRAINT, btree (sn)
Has OIDs: no
Table "public.table_b"
Column | Type | Modifiers | Storage | Stats target | Description
--------------+-----------------------------+-----------+----------+--------------+-------------
sn | numeric | | main | |
ettime | timestamp without time zone | | plain | |
value | text | | extended | |
comment | text | | extended | |
l_id | numeric | | main | |
n_id | numeric | | main | |
ettime.y | timestamp without time zone | | plain | |
s_id2 | numeric | | main | |
e_id2 | numeric | | main | |
Indexes:
"table_b_sn_key" UNIQUE CONSTRAINT, btree (sn)
Has OIDs: no
通过使用下面的脚本我会得到想要的结果。
库（RPostgreSQL）
M1 <- dbGetQuery(con, "select
a.r_date::date date,
downgraded,
total,
round(downgraded::numeric/total* 100, 2) percentage
from (
select date_trunc('day', eventtime) r_date, count(*) downgraded
from table_b
where s_id2 in (59,07)
group by 1
) b
join (
select date_trunc('day', eventtime) r_date, count(*) total
from table_a
where s_id1 in (59,07)
group by 1
) a
using (r_date)
order by 1")
由于我不是编程出身，所以我对每台机器都使用上面的完整查询语句
M2 <- dbGetQuery(con, "select
a.r_date::date date,
downgraded,
total, ........
........
M3 <- dbGetQuery(con, "select
a.r_date::date date,
downgraded,
total,.....
.........
在我的例子中，是否可以使用循环而不是对每台机器使用查询。这样在一个查询中我将获得所有机器数据。
谁能告诉我如何用我的例子做这些。实际上我需要 运行 6 个单独的脚本，在每个脚本中我需要三台不同机器的数据。
只需修改您的 SQL 查询以考虑其他机器。不需要 R 解决方法。事实上，您将所有数据重组和处理都保留在 SQL 引擎上。具体来说，将 s_id 添加到派生表中的 where 子句（和 group by）或使用联合查询。在两者中，都添加了 machine 和 s_id 列以在导入的数据框中识别它们：
条款更改的地方
strsql <- "select a.machine,
a.r_date::date date,
downgraded,
total,
round(downgraded::numeric/total* 100, 2) percentage
from (
select CASE WHEN s_id2 IN (59,07) THEN 'M1'
WHEN s_id2 IN (60,92) THEN 'M2'
WHEN s_id2 IN (95,109) THEN 'M3'
END As machine, date_trunc('day', eventtime) r_date,
count(*) downgraded
from table_b
where s_id2 in (59,07,60,92,95,109)
group by CASE WHEN s_id2 IN (59,07) THEN 'M1'
WHEN s_id2 IN (60,92) THEN 'M2'
WHEN s_id2 IN (95,109) THEN 'M3'
END, date_trunc('day', eventtime)
) b
inner join (
select CASE WHEN s_id1 IN (59,07) THEN 'M1'
WHEN s_id1 IN (60,92) THEN 'M2'
WHEN s_id1 IN (95,109) THEN 'M3'
END As machine, date_trunc('day', eventtime) r_date,
count(*) total
from table_a
where s_id1 in (59,07,60,92,95,109)
group by CASE WHEN s_id1 IN (59,07) THEN 'M1'
WHEN s_id1 IN (60,92) THEN 'M2'
WHEN s_id1 IN (95,109) THEN 'M3'
END, date_trunc('day', eventtime)
) a
on a.machine = b.machine and a.r_date = b.r_date
order by a.r_date;"
machinesdf <- dbGetQuery(con, strsql)
联合查询
strsql <- "select a.machine,
a.r_date::date date,
downgraded,
total,
round(downgraded::numeric/total* 100, 2) percentage
from (
select 'M1' as machine, date_trunc('day', eventtime) r_date,
count(*) downgraded
from table_b
where s_id2 in (59,07)
group by date_trunc('day', eventtime)
) b
inner join (
select 'M1' as machine, date_trunc('day', eventtime) r_date,
count(*) total
from table_a
where s_id1 in (59,07)
group by date_trunc('day', eventtime)
) a
on a.machine = b.machine and a.r_date = b.r_date
order by a.r_date
union
select a.machine,
a.r_date::date date,
downgraded,
total,
round(downgraded::numeric/total* 100, 2) percentage
from (
select 'M2' as machine, date_trunc('day', eventtime) r_date,
count(*) downgraded
from table_b
where s_id2 in (60,92)
group by date_trunc('day', eventtime)
) b
inner join (
select 'M2' as machine, date_trunc('day', eventtime) r_date,
count(*) total
from table_a
where s_id1 in (60,92)
group by date_trunc('day', eventtime)
) a
on a.machine = b.machine and a.r_date = b.r_date
union
select a.machine,
a.r_date::date date,
downgraded,
total,
round(downgraded::numeric/total* 100, 2) percentage
from (
select 'M3' as machine, date_trunc('day', eventtime) r_date,
count(*) downgraded
from table_b
where s_id2 in (95,109)
group by date_trunc('day', eventtime)
) b
inner join (
select 'M3' as machine, date_trunc('day', eventtime) r_date,
count(*) total
from table_a
where s_id1 in (95,109)
group by date_trunc('day', eventtime)
) a
on a.machine = b.machine and a.r_date = b.r_date;"
machinesdf <- dbGetQuery(con, strsql)
我的数据库中有两个表。两个表中的列及其数据类型如下所示。假设两个表都存储 3 台机器的数据。每台机器都有两个 s_id，通过使用它们，我将 select 特定机器所需的数据。
每台机器的s_id是
m1 59,07
m2 60,92
m3 95,109
Table "public.table_a"
Column | Type | Modifiers | Storage | Stats target | Description
--------------+-----------------------------+-----------+---------+--------------+-------------
ettime | timestamp without time zone | | plain | |
sn | numeric | | main | |
s_id1 | numeric | | main | |
e_id1 | numeric | | main | |
Indexes:
"table_a_sn_key" UNIQUE CONSTRAINT, btree (sn)
Has OIDs: no
Table "public.table_b"
Column | Type | Modifiers | Storage | Stats target | Description
--------------+-----------------------------+-----------+----------+--------------+-------------
sn | numeric | | main | |
ettime | timestamp without time zone | | plain | |
value | text | | extended | |
comment | text | | extended | |
l_id | numeric | | main | |
n_id | numeric | | main | |
ettime.y | timestamp without time zone | | plain | |
s_id2 | numeric | | main | |
e_id2 | numeric | | main | |
Indexes:
"table_b_sn_key" UNIQUE CONSTRAINT, btree (sn)
Has OIDs: no
通过使用下面的脚本我会得到想要的结果。
库（RPostgreSQL）
M1 <- dbGetQuery(con, "select
a.r_date::date date,
downgraded,
total,
round(downgraded::numeric/total* 100, 2) percentage
from (
select date_trunc('day', eventtime) r_date, count(*) downgraded
from table_b
where s_id2 in (59,07)
group by 1
) b
join (
select date_trunc('day', eventtime) r_date, count(*) total
from table_a
where s_id1 in (59,07)
group by 1
) a
using (r_date)
order by 1")
由于我不是编程出身，所以我对每台机器都使用上面的完整查询语句
M2 <- dbGetQuery(con, "select
a.r_date::date date,
downgraded,
total, ........
........
M3 <- dbGetQuery(con, "select
a.r_date::date date,
downgraded,
total,.....
.........
在我的例子中，是否可以使用循环而不是对每台机器使用查询。这样在一个查询中我将获得所有机器数据。
谁能告诉我如何用我的例子做这些。实际上我需要 运行 6 个单独的脚本，在每个脚本中我需要三台不同机器的数据。
只需修改您的 SQL 查询以考虑其他机器。不需要 R 解决方法。事实上，您将所有数据重组和处理都保留在 SQL 引擎上。具体来说，将 s_id 添加到派生表中的 where 子句（和 group by）或使用联合查询。在两者中，都添加了 machine 和 s_id 列以在导入的数据框中识别它们：
条款更改的地方
strsql <- "select a.machine,
a.r_date::date date,
downgraded,
total,
round(downgraded::numeric/total* 100, 2) percentage
from (
select CASE WHEN s_id2 IN (59,07) THEN 'M1'
WHEN s_id2 IN (60,92) THEN 'M2'
WHEN s_id2 IN (95,109) THEN 'M3'
END As machine, date_trunc('day', eventtime) r_date,
count(*) downgraded
from table_b
where s_id2 in (59,07,60,92,95,109)
group by CASE WHEN s_id2 IN (59,07) THEN 'M1'
WHEN s_id2 IN (60,92) THEN 'M2'
WHEN s_id2 IN (95,109) THEN 'M3'
END, date_trunc('day', eventtime)
) b
inner join (
select CASE WHEN s_id1 IN (59,07) THEN 'M1'
WHEN s_id1 IN (60,92) THEN 'M2'
WHEN s_id1 IN (95,109) THEN 'M3'
END As machine, date_trunc('day', eventtime) r_date,
count(*) total
from table_a
where s_id1 in (59,07,60,92,95,109)
group by CASE WHEN s_id1 IN (59,07) THEN 'M1'
WHEN s_id1 IN (60,92) THEN 'M2'
WHEN s_id1 IN (95,109) THEN 'M3'
END, date_trunc('day', eventtime)
) a
on a.machine = b.machine and a.r_date = b.r_date
order by a.r_date;"
machinesdf <- dbGetQuery(con, strsql)
联合查询
strsql <- "select a.machine,
a.r_date::date date,
downgraded,
total,
round(downgraded::numeric/total* 100, 2) percentage
from (
select 'M1' as machine, date_trunc('day', eventtime) r_date,
count(*) downgraded
from table_b
where s_id2 in (59,07)
group by date_trunc('day', eventtime)
) b
inner join (
select 'M1' as machine, date_trunc('day', eventtime) r_date,
count(*) total
from table_a
where s_id1 in (59,07)
group by date_trunc('day', eventtime)
) a
on a.machine = b.machine and a.r_date = b.r_date
order by a.r_date
union
select a.machine,
a.r_date::date date,
downgraded,
total,
round(downgraded::numeric/total* 100, 2) percentage
from (
select 'M2' as machine, date_trunc('day', eventtime) r_date,
count(*) downgraded
from table_b
where s_id2 in (60,92)
group by date_trunc('day', eventtime)
) b
inner join (
select 'M2' as machine, date_trunc('day', eventtime) r_date,
count(*) total
from table_a
where s_id1 in (60,92)
group by date_trunc('day', eventtime)
) a
on a.machine = b.machine and a.r_date = b.r_date
union
select a.machine,
a.r_date::date date,
downgraded,
total,
round(downgraded::numeric/total* 100, 2) percentage
from (
select 'M3' as machine, date_trunc('day', eventtime) r_date,
count(*) downgraded
from table_b
where s_id2 in (95,109)
group by date_trunc('day', eventtime)
) b
inner join (
select 'M3' as machine, date_trunc('day', eventtime) r_date,
count(*) total
from table_a
where s_id1 in (95,109)
group by date_trunc('day', eventtime)
) a
on a.machine = b.machine and a.r_date = b.r_date;"
machinesdf <- dbGetQuery(con, strsql)