Efficient SQL Query on Hive for max value - sql

I have the following table of data (as Delta table, which is mapped as Hive table)
UtilEvents:
-----------------------------------------------------------------------------
SerialNumber EventTime UseCase RemoteHost RemoteIP
-----------------------------------------------------------------------------
131058 2022-12-02T00:31:29 Send Host1 RemoteIP1
131058 2022-12-21T00:33:24 Receive Host1 RemoteIP1
131058 2022-12-22T01:35:33 Send Host1 RemoteIP1
131058 2022-12-20T01:36:53 Receive Host1 RemoteIP1
131058 2022-12-11T00:33:28 Send Host2 RemoteIP2
131058 2022-12-15T00:35:18 Receive Host2 RemoteIP2
131058 2022-12-12T02:29:11 Send Host2 RemoteIP2
131058 2022-12-01T02:30:56 Receive Host2 RemoteIP2
I need a result set which is grouped by UseCase and RemoteHost, but with max value of EventTime.
So the result should look something like :
Result_UtilEvents:
----------------------------------------------------------------
SerialNumber EventTime UseCase RemoteHost
----------------------------------------------------------------
131058 2022-12-21T00:33:24 Receive Host1
131058 2022-12-22T01:35:33 Send Host1
131058 2022-12-15T00:35:18 Receive Host2
131058 2022-12-12T02:29:11 Send Host2
Could you suggest an efficient Databricks SQL Query which can give this result.
PS : Intermediate dataframe results can not be used in this case. It has to be in pure SQL format.

I think that you just need to group by and get max together with column on which you are grouping. I added SerialNumber to group by as it is not clear how to treat this column
import datetime
import pyspark.sql.functions as F
x = [
(131058, datetime.datetime(2022, 12, 2, 0, 31, 29), "Send", "Host1", "RemoteIP1"),
(131058, datetime.datetime(2022, 12, 21, 0, 33, 24), "Receive", "Host1", "RemoteIP1"),
(131058, datetime.datetime(2022, 12, 22, 1, 35, 33), "Send", "Host1", "RemoteIP1"),
(131058, datetime.datetime(2022, 12, 20, 1, 36, 53), "Receive", "Host1", "RemoteIP1"),
(131058, datetime.datetime(2022, 12, 11, 0, 33, 28), "Send", "Host2", "RemoteIP2"),
(131058, datetime.datetime(2022, 12, 15, 0, 35, 18), "Receive", "Host2", "RemoteIP2"),
(131058, datetime.datetime(2022, 12, 12, 2, 29, 11), "Send", "Host2", "RemoteIP2"),
(131058, datetime.datetime(2022, 12, 1, 2, 30, 56), "Receive", "Host2", "RemoteIP2")
]
df = spark.createDataFrame(x, schema=["SerialNumber", "EventTime", "UseCase", "RemoteHost", "RemoteIp"])
df.createOrReplaceTempView("test_table")
spark.sql(
"select SerialNumber, Max(EventTime) as EventTime, UseCase, RemoteHost "
"from test_table "
"group by SerialNumber, UseCase, RemoteHost"
).show()
output
+------------+-------------------+-------+----------+
|SerialNumber| EventTime|UseCase|RemoteHost|
+------------+-------------------+-------+----------+
| 131058|2022-12-22 01:35:33| Send| Host1|
| 131058|2022-12-21 00:33:24|Receive| Host1|
| 131058|2022-12-12 02:29:11| Send| Host2|
| 131058|2022-12-15 00:35:18|Receive| Host2|
+------------+-------------------+-------+----------+

Related

How to correctly format a pd-multiindex for sktime?

I have a pd.multiindex which looks like this:
However, when I use the run check_raise(df_train, mtype="pd-multiindex)"
I get the following error:
File /Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/sktime/datatypes/_check.py:252, in check_raise(obj, mtype, scitype, var_name)
250 return True
251 else:
--> 252 raise TypeError(msg)
TypeError: input.loc[i] must be Series of mtype pd.DataFrame, not at i=[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25]
I believe this means I am meant to convert each row into a pandas series, but I am unsure if this is correct?
Any help would be appreciated.
I have similar issue, try to check if your index have duplicate keys, in your case:
df_train.reset_index(['sbj', 'system_time_stamp'])[['sbj', 'system_time_stamp']].duplicated(keep=False)
Remove duplicated index works for me.

This prime generating function using generateSequence in Kotlin is not easy to understand. :(

val primes = generateSequence(2 to generateSequence(3) {it + 2}) {
val currSeq = it.second.iterator()
val nextPrime = currSeq.next()
nextPrime to currSeq.asSequence().filter { it % nextPrime != 0}
}.map {it.first}
println(primes.take(10).toList()) // prints [2, 3, 5, 7, 11, 13, 17, 19, 23, 29]
I tried to understand this function about how it works, but not easy to me.
Could someone explain how it works? Thanks.
It generates an infinite sequence of primes using the "Sieve of Eratosthenes" (see here: https://en.wikipedia.org/wiki/Sieve_of_Eratosthenes).
This implementation uses a sequence of pairs to do this. The first element of every pair is the current prime, and the second element is a sequence of integers larger than that prime which is not divisible by any previous prime.
It starts with the pair 2 to [3, 5, 7, 9, 11, 13, 15, 17, ...], which is given by 2 to generateSequence(3) { it + 2 }.
Using this pair, we create the next pair of the sequence by taking the first element of the sequence (which is now 3), and then removing all numbers divisible by 3 from the sequence (removing 9, 15, 21 and so on). This gives us this pair: 3 to [5, 7, 11, 13, 17, ...]. Repeating this pattern will give us all primes.
After creating a sequence of pairs like this, we are finally doing .map { it.first } to pick only the actual primes, and not the inner sequences.
The sequence of pairs will evolve like this:
2 to [3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, ...]
3 to [5, 7, 11, 13, 17, 19, 23, 25, 29, ...]
5 to [7, 11, 13, 17, 19, 23, 29, ...]
7 to [11, 13, 17, 19, 23, 29, ...]
11 to [13, 17, 19, 23, 29, ...]
13 to [17, 19, 23, 29, ...]
// and so on

Inserting new fields(columns) to mongoDB with pandas

I have an existing data in MongoDB where Primary Key is set on 'date' with a few fields in it.
And I want to insert a new pandas dataframe with new fields(columns) to the existing data in MongoDB, joining on the 'date' field which exists on the both dataframe.
For example, lets say the this is dataframe A I have in my MongoDB ( I set the index with 'date' field when calling the data from MongoDB)
And this is the new dataframe B I want to insert to MongoDB
And this is the final dataframe C with new fields( 'std_50_3000window', 'std_50_300window', 'std_50_500window' added on 'date' index), which I want it to have on my MongoDB.
Is there any way to do this?? (Maybe with insert_many method?)
The method you need is update_one() with upsert=True in a loop; you can't use insert_many() for two reasons; firstly your not always inserting; sometime you are updating; secondly update_many() (and insert_many()) only work on a single filter; in your case each filter is different as each update relates to a different time.
This is generic solution that will combine dataframes (df_a, df_b in this case - you can have as many as you like) in the manner that you need. It uses iterrows to get each row of the dataframe, filters on the date, and sets the values to those in the dataframe. the $set operator will override values if they are there already and set them if not set. upsert=True will perform an insert if there's no match on the date.
for df in [df_a, df_b]:
for _, row in df.iterrows():
db.mycollection.update_one({'date': row.get('date')}, {'$set': row.to_dict()}, upsert=True)
Full worked example:
from pymongo import MongoClient
from pprint import pprint
import datetime
import pandas as pd
# Sample data setup
db = MongoClient()['mydatabase']
data_a = [[datetime.datetime(2017, 5, 19, 21, 20), 96, 8, 98],
[datetime.datetime(2017, 5, 19, 21, 21), 95, 8, 97],
[datetime.datetime(2017, 5, 19, 21, 22), 95, 8, 97]]
df_a = pd.DataFrame(data_a, columns=['date', 'std_500_1000window', 'std_50_100window', 'std_50_2000window'])
data_b = [[datetime.datetime(2017, 5, 19, 21, 20), 98, 9, 10],
[datetime.datetime(2017, 5, 19, 21, 21), 98, 9, 10],
[datetime.datetime(2017, 5, 19, 21, 22), 98, 9, 10]]
df_b = pd.DataFrame(data_b, columns=['date', 'std_50_3000window', 'std_50_300window', 'std_50_500window'])
# Perform the upserts
for df in [df_a, df_b]:
for _, row in df.iterrows():
db.mycollection.update_one({'date': row.get('date')}, {'$set': row.to_dict()}, upsert=True)
# Print the results
for record in db.mycollection.find():
pprint(record)
Result:
{'_id': ObjectId('5f0ae909df5531ac655ce528'),
'date': datetime.datetime(2017, 5, 19, 21, 20),
'std_500_1000window': 96,
'std_50_100window': 8,
'std_50_2000window': 98,
'std_50_3000window': 98,
'std_50_300window': 9,
'std_50_500window': 10}
{'_id': ObjectId('5f0ae909df5531ac655ce52a'),
'date': datetime.datetime(2017, 5, 19, 21, 21),
'std_500_1000window': 95,
'std_50_100window': 8,
'std_50_2000window': 97,
'std_50_3000window': 98,
'std_50_300window': 9,
'std_50_500window': 10}
{'_id': ObjectId('5f0ae909df5531ac655ce52c'),
'date': datetime.datetime(2017, 5, 19, 21, 22),
'std_500_1000window': 95,
'std_50_100window': 8,
'std_50_2000window': 97,
'std_50_3000window': 98,
'std_50_300window': 9,
'std_50_500window': 10}

MatPlotLib with custom dictionaries convert to graphs

Problem:
I have a list of ~108 dictionaries named list_of_dictionary and I would like to use Matplotlib to generate line graphs.
The dictionaries have the following format (this is one of 108):
{'price': [59990,
59890,
60990,
62990,
59990,
59690],
'car': '2014 Land Rover Range Rover Sport',
'datetime': [datetime.datetime(2020, 1, 22, 11, 19, 26),
datetime.datetime(2020, 1, 23, 13, 12, 33),
datetime.datetime(2020, 1, 28, 12, 39, 24),
datetime.datetime(2020, 1, 29, 18, 39, 36),
datetime.datetime(2020, 1, 30, 18, 41, 31),
datetime.datetime(2020, 2, 1, 12, 39, 7)]
}
Understanding the dictionary:
The car 2014 Land Rover Range Rover Sport was priced at:
59990 on datetime.datetime(2020, 1, 22, 11, 19, 26)
59890 on datetime.datetime(2020, 1, 23, 13, 12, 33)
60990 on datetime.datetime(2020, 1, 28, 12, 39, 24)
62990 on datetime.datetime(2020, 1, 29, 18, 39, 36)
59990 on datetime.datetime(2020, 1, 30, 18, 41, 31)
59690 on datetime.datetime(2020, 2, 1, 12, 39, 7)
Question:
With this structure how could one create mini-graphs with matplotlib (say 11 rows x 10 columns)?
Where each mini-graph will have:
the title of the graph frome car
x-axis from the datetime
y-axis from the price
What I have tried:
df = pd.DataFrame(list_of_dictionary)
df = df.set_index('datetime')
print(df)
I don't know what to do thereafter...
Relevant Research:
Plotting a column containing lists using Pandas
Pandas column of lists, create a row for each list element
I've read these multiple times, but the more I read it, the more confused I get :(.
I don't know if it's sensible to try and plot that many plots on a figure. You'll have to make some choices to be able to fit all the axes decorations on the page (titles, axes labels, tick labels, etc...).
but the basic idea would be this:
car_data = [{'price': [59990,
59890,
60990,
62990,
59990,
59690],
'car': '2014 Land Rover Range Rover Sport',
'datetime': [datetime.datetime(2020, 1, 22, 11, 19, 26),
datetime.datetime(2020, 1, 23, 13, 12, 33),
datetime.datetime(2020, 1, 28, 12, 39, 24),
datetime.datetime(2020, 1, 29, 18, 39, 36),
datetime.datetime(2020, 1, 30, 18, 41, 31),
datetime.datetime(2020, 2, 1, 12, 39, 7)]
}]*108
fig, axs = plt.subplots(11,10, figsize=(20,22)) # adjust figsize as you please
for car,ax in zip(car_data, axs.flat):
ax.plot(car["datetime"], car['price'], '-')
ax.set_title(car['car'])
Ideally, all your axes could share the same x and y axes so you could have the labels only on the left-most and bottom-most axes. This is taken care of automatically if you add sharex=True and sharey=True to subplots():
fig, axs = plt.subplots(11,10, figsize=(20,22), sharex=True, sharey=True) # adjust figsize as you please

regex text parser

I have the dataframe like
ID Series
1102 [('taxi instructions', 13, 30, 'NP'), ('consistent basis', 31, 47, 'NP'), ('the atc taxi clearance', 89, 111, 'NP')]
1500 [('forgot data pages info', 0, 22, 'NP')]
649 [('hud', 0, 3, 'NP'), ('correctly fotr approach', 12, 35, 'NP')]
I am trying to parse the text in column named Series to different columns named Series1 Series2 etc upto the highest number of texts parsed.
df_parsed = df['Series'].str[1:-1].str.split(', ', expand = True)
something like this:
ID Series Series1 Series2 Series3
1102 [('taxi instructions', 13, 30, 'NP'), ('consistent basis', 31, 47, 'NP'), ('the atc taxi clearance', 89, 111, 'NP')] taxi instructions consistent basis the atc taxi clearance
1500 [('forgot data pages info', 0, 22, 'NP')] forgot data pages info
649 [('hud', 0, 3, 'NP'), ('correctly fotr approach', 12, 35, 'NP')] hud correctly fotr approach
The format of your final result is not easy to understand, but maybe you can follow the concept to create your new columns:
def process(ls):
return ' '.join([x[0] for x in ls])
df['Series_new'] = df['Series'].apply(lambda x: process(x))
And if you want to create N new columns (N = max_len(Series_list)), I think you can calculate N first. Then, follow the concept above and fill in NaN properly to create N new columns.