When I do psql --no-align --field-separator ',', I get CSV output with a header containing field names and a trailer telling me how many rows were found. To pass that into an analysis program, I need the header but not the trailer. I can surely write a filter to pass the first N-1 lines of the psql output but I'd prefer to suppress the trailer. Is there an option I'm missing that will turn on the header with --tuples-only or turn off the trailer?
psql --no-align --field-separator ',' --pset footer will turn off the row summary footer
I found
COPY (...query...) TO STDOUT WITH CSV HEADER;
at http://blogs.law.harvard.edu/dlarochelle/2011/12/11/outputing-to-csv-in-postgresql/.
It doesn't seem to work without the TO STDOUT but I can work with that.
Related
I receive a .csv export every 10 minutes that I'd like to import into a postgreSQL server. Working with a test csv, I got everything to work, but didn't take notice that my actual csv file has a forced ":" at the end of each column header (but not on the first header for some reason)(built into the back-end of the exporter, so I cant get it removed, already asked the company). So I added the ":"s to my test csv as shown in the link,
My insert into functions no longer work and give me syntax errors. First I'm trying to add them using the following code,
print("Reading file contents and copying into table...")
with open('C:\\Users\\admin\\Desktop\\test2.csv') as csvfile:
readCSV = csv.reader(csvfile, delimiter=',')
columns = next(readCSV) #skips the header row
query = 'insert into test({0}) values ({1})'
query = query.format(','.join(columns), ','.join('?' * len(columns)))
for data in readCSV:
cursor.execute(query, data)
con.commit()
Resulting in '42601' error near ":" in the second column header.
The results are the same while actually listing column headers and ? ? ?s out in the INSERT INTO section.
What is the syntax to get the script to accept ":" on column headers? If there's no way, is there a way to scan through headers and remove the ":" at the end of each?
Because : is a special character, if your column is named year: in the DB, you must double quote its name --> select "year:" from test;
You are getting a PG error because you are referencing the unquoted column name (insert into test({0})), so add double quotes there.
query = 'insert into test("year:","day:", "etc:") values (...)'
That being said, it might be simpler to remove every occurrence of : in your csv's 1st line
Much appreciated JGH and Adrian. I went with your suggestion to remove every occurrence of : by adding the following line after the first columns = ... statement
columns = [column.strip(':') for column in columns]
It worked well.
I try to read a csv file containing real numbers with a comma as separator. I try to read this file with \copy in psql:
\copy table FROM 'filename.csv' DELIMITER ';' CSV HEADER;
psql does not recognize the comma as decimal point.
psql:filename.sql:44: ERROR: invalid input syntax for type real: "9669,84"
CONTEXT: COPY filename, line 2, column col-3: "9669,84"
I did some googling but could not find any answer other than "change the decimal comma into a decimal point". I tried SET DECIMALSEPARATORCOMMA=ON; but that did not work. I also experimented with some encoding but I couldn't find whether encoding governs the decimal point (I got the impression it didn't).
Is there really no solution other than changing the input data?
COPY to a table where you insert the number into a varchar field. Then do something like in psql:
--Temporarily change numeric formatting to one that uses ',' as
--decimal separator.
set lc_numeric = "de_DE.UTF-8";
--Below is just an example. In your case the select would be part of
--insert into the target table. Also the first part of to_number
--would be the field from your staging table.
select to_number('9669,84', '99999D999');
9669.84
You might need to change the format string to match all the numbers. For more information on what is available see Data formatting Table 9.28. Template Patterns for Numeric Formatting.
I added a dummy column at the beginning of my data export to a CSV file to get rid of control characters and some specific string values as mentioned below by using a pipe '|' delimiter. This data is coming from Teradata fast export using utf-8
'''
y^CDUMMYCOLUMN|
<86>^ADUMMYCOLUMN|
<87>^ADUMMYCOLUMN|
<94>^ADUMMYCOLUMN|
{^ADUMMYCOLUMN|
_^ADUMMYCOLUMN|
y^CDUMMYCOLUMN|
[^ADUMMYCOLUMN|
k^ADUMMYCOLUMN|
m^ADUMMYCOLUMN|
<82>^ADUMMYCOLUMN|
c^ADUMMYCOLUMN|
<8e>^ADUMMYCOLUMN|
<85>^ADUMMYCOLUMN|
'''
This is completely random and not every row has these special characters. I'm sure I'm missing something here. I'm using sed to get rid of dummycolumn and control characters.
'''$ sed -e 's/.*DUMMYCOLUMN|//;/^$/d' data.csv > data_output.csv'''
After running this statement, I'm still remaining these below random values.
'''
<86>
<87>
<85>
<94>
<8a>
<85>
<8e>
'''
I could have written a sed statement to remove first three letters from each row but this series is not appearing in every row. At the same time, row count is 400 Million.
Current output.
y^CDUMMYCOLUMN|COLUMN1|COLUMN2|COLUMN3
<86>^ADUMMYCOLUMN|6218915846|36596|12
<87>^ADUMMYCOLUMN|9822354765|35325|33
t^ADUMMYCOLUMN|6788793999|111|12
g^ADUMMYCOLUMN|6090724004|7017|12
_^ADUMMYCOLUMN|IC-21357688806502|111|12
<8e>^ADUMMYCOLUMN|9682027117|35335|33
v^ADUMMYCOLUMN|6406807681|121|12
h^ADUMMYCOLUMN|6346768510|121|12
V^ADUMMYCOLUMN|6130452510|7017|12
Desired Output
COLUMN1|COLUMN2|COLUMN3
6218915846|36596|12
9822354765|35325|33
6788793999|111|12
6090724004|7017|12
IC-21357688806502|111|12
9682027117|35335|33
6406807681|121|12
6346768510|121|12
6130452510|7017|12
Please help.
Thank you.
I have a requirement to replace multiple columns of a csv file with its base64 encoding value which should be applied to some columns of the file but keep the first line unaffected as the first line contains the header of the file. I have tried out for 1 column as below but as I have given it to proceed after skipping the first line of the file it is not
gawk 'BEGIN { FS="|"; OFS="|" } NR >=2 { cmd="echo "$4" | base64 -w 0";cmd | getline x;close(cmd); print $1,$2,$3,x}' awktest
o/p:
12|A|B|Qw==
13|C|D|RQ==
36|Z|V|VQ==
Qs: It is not showing the header in the output. What should I do to make produce the header in the output? Also can I use any loop here to replace multiple columns?
input:
10|A|B|C|5|T|R
12|A|B|C|6|eee|ff
13|C|D|E|9|dr|xrdd
36|Z|V|U|7|xc|xd
Required output:
10|A|B|C|5|T|R
12|A|B|encodedvalue|6|encodedvalue|ff
13|C|D|encodedvalue|9|encodedvalue|xrdd
36|Z|V|encodedvalue|7|encodedvalue|xd
Is this possible? Have researched a lot but could not find a proper explanation. I am new to shell. Kindly help. Many thanks!!!!
It looks like you can just sequence conditionals. This may not be the best way of solving the header issue, but it's intuitive.
BEGIN { FS="|"; OFS="|" } NR ==1 {print} NR >=2 { cmd="echo "$4" | base64 -w 0";cmd | getline x;close(cmd); print $1,$2,$3,x}
As for using a loop to affect multiple columns... Loops in bash are hard. Awk is technically its own language, and may have a looping construct of it's own, IDK. But it's not clear you need a loop. If there's only a reasonable number of fields that need modifying, you can just parameterize the existing command (somehow) by the field index, and then pipe through however many instances of it. It won't be as performant as doing it all in a single pass of awk, but that's probably ok.
There's 1 column that contains commas. When I output my query to csv, these commas break the csv format. What I've been doing to avoid this is a simple
replace(A."Sales Rep",',','')
Is there a better way of doing this so that I can actually get the commas in the final output without breaking the csv file?
Thanks!
You can use the COPY command to get PostgreSQL to build the CSV for you:
COPY -- copy data between a file and a table
Something like one of these:
copy your_table to 'filename' csv
copy your_table to 'filename' csv force quote *
copy your_table to stdout csv force quote *
copy your_table to stdout csv force quote * header
...
You have to be the super user to copy to a filename though. If you're inside psql, you can use the \copy command:
Performs a frontend (client) copy. This is an operation that runs an SQL COPY command, but instead of the server reading or writing the specified file, psql reads or writes the file and routes the data between the server and the local file system.
The syntax is pretty much the same:
\copy your_table to 'filename.csv' csv force quote * header
...
Quote the fields with "
a,this has a , in it,b
would become
a,"this has a, in it",b
and if the fields have BOTH a , and a ", double the quotes:
a,this has a " and , in it,b
becomes
a,"this has a "" and , in it",b