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How to get null counts of each rows except one column?


By : Viplav M
Date : July 31 2020, 10:00 PM
like below fixes the issue You can select all columns without first by DataFrame.iloc:
code :
null_counts = irs_df.iloc[:, 1:].isnull().sum()
print (null_counts)
First_Name    1
Age           1
dtype: int64
null_counts = irs_df.drop('Last_Name', axis=1).isnull().sum()
print (null_counts)
First_Name    1
Age           1
dtype: int64


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SQL COUNT(Column) Counts also the null value which is wrong


By : DzungLM
Date : March 29 2020, 07:55 AM
I hope this helps . Actually, a IS NOT NULL condition like mentioned in all the answers is not necessary since count(columnName) will not count null values. So basically it enough to just filter empty string values and just specify the column in the count.
code :
SELECT COUNT(columnName) as TotalColumnValue
FROM tblNam
WHERE columnName <> ''

How to Filter Out All column = null Rows Past the Last column != null Row, by an Offset, in the Result of a SQL Query


By : Raj
Date : March 29 2020, 07:55 AM
I wish this helpful for you I make this example in SQL SERVER same code should work in oracle
code :
SELECT *
from Events
WHERE Flow <= (SELECT max(Flow) + 3*10 FROM Events WHERE [HEAD] IS NOT NULL)
WITH addRow_id as (
     SELECT *, ROW_NUMBER() OVER ( ORDER BY [Flow], [Series_Name]) as rn
     FROM Events
),
lastID as (
     SELECT MAX(rn) as last_row
     FROM addRow_id
     WHERE [HEAD] IS NOT NULL
)
SELECT *
FROM addRow_id A
CROSS JOIN lastID L
WHERE A.rn <= L.last_row + 6;

How to get the null counts for each column in a table with 500 columns?


By : user6702921
Date : March 29 2020, 07:55 AM
like below fixes the issue My use case is to calculate the null counts for each column in a table(which is having 500 columns)..i cannot do manually because of this large number of columns..Can anyone please suggest me how to proceed on this... , For any given column you can, of course, just run:
code :
select count(1) from column_name where column_name is null
SELECT 'select \'spacer\' AS column_name, 0 AS null_count ' union all
SELECT 'union all select \'' || "column" || '\', count(1) from ' || tablename || ' where ' || "column" || ' is null'
FROM pg_table_def
WHERE tablename = 'users'
AND NOT "notnull"
SELECT 'select' UNION ALL SELECT 'count(nvl2(' || "column" || ',null,1)) as ' || "column" || ', '
FROM pg_table_def
WHERE tablename = 'users'
AND   NOT "notnull"
UNION ALL
SELECT 'null as spacer from users '

How to create a column which counts occurrences within another column and does not aggregate rows in python?


By : Bio-engineer
Date : March 29 2020, 07:55 AM
help you fix your problem I need to count the occurrences of specific elements within a column and add the count of occurrences as an additional column without removing rows. , You are close, need specify column after groupby:
code :
df['count'] = df.groupby('no_')['no_'].transform('count') 
df['counts']= df.no_.map(df.no_.value_counts())

print (df)
   id  no_  counts
0   1    1       1
1   2    3       2
2   3    3       2
3   4    4       1
4   5    2       1

Hive Sql dynamically get null column counts from a table


By : Jeff Wheeler
Date : March 29 2020, 07:55 AM
Hope that helps In the following solution there is no need to deal with each column separately. The result is a column index and the number of null values in that column.
You can later on join it by the column index to an information retrieved from the metastore.
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