Save PL/pgSQL output from PostgreSQL to a CSV file

Question

What is the easiest way to save PL/pgSQL output from a PostgreSQL database to a CSV file?

I\'m using PostgreSQL 8.4 with pgAdmin III and PSQL plugin where I run que

Answer 1

I've written a little tool called psql2csv that encapsulates the COPY query TO STDOUT pattern, resulting in proper CSV. It's interface is similar to psql.

psql2csv [OPTIONS] < QUERY
psql2csv [OPTIONS] QUERY

The query is assumed to be the contents of STDIN, if present, or the last argument. All other arguments are forwarded to psql except for these:

-h, --help           show help, then exit
--encoding=ENCODING  use a different encoding than UTF8 (Excel likes LATIN1)
--no-header          do not output a header

Answer 2

CSV Export Unification

This information isn't really well represented. As this is the second time I've needed to derive this, I'll put this here to remind myself if nothing else.

Really the best way to do this (get CSV out of postgres) is to use the COPY ... TO STDOUT command. Though you don't want to do it the way shown in the answers here. The correct way to use the command is:

COPY (select id, name from groups) TO STDOUT WITH CSV HEADER

Remember just one command!

It's great for use over ssh:

$ ssh psqlserver.example.com 'psql -d mydb "COPY (select id, name from groups) TO STDOUT WITH CSV HEADER"' > groups.csv

It's great for use inside docker over ssh:

$ ssh pgserver.example.com 'docker exec -tu postgres postgres psql -d mydb -c "COPY groups TO STDOUT WITH CSV HEADER"' > groups.csv

It's even great on the local machine:

$ psql -d mydb -c 'COPY groups TO STDOUT WITH CSV HEADER' > groups.csv

Or inside docker on the local machine?:

docker exec -tu postgres postgres psql -d mydb -c 'COPY groups TO STDOUT WITH CSV HEADER' > groups.csv

Or on a kubernetes cluster, in docker, over HTTPS??:

kubectl exec -t postgres-2592991581-ws2td 'psql -d mydb -c "COPY groups TO STDOUT WITH CSV HEADER"' > groups.csv

So versatile, much commas!

Do you even?

Yes I did, here are my notes:

The COPYses

Using /copy effectively executes file operations on whatever system the psql command is running on, as the user who is executing it1. If you connect to a remote server, it's simple to copy data files on the system executing psql to/from the remote server.

COPY executes file operations on the server as the backend process user account (default postgres), file paths and permissions are checked and applied accordingly. If using TO STDOUT then file permissions checks are bypassed.

Both of these options require subsequent file movement if psql is not executing on the system where you want the resultant CSV to ultimately reside. This is the most likely case, in my experience, when you mostly work with remote servers.

It is more complex to configure something like a TCP/IP tunnel over ssh to a remote system for simple CSV output, but for other output formats (binary) it may be better to /copy over a tunneled connection, executing a local psql. In a similar vein, for large imports, moving the source file to the server and using COPY is probably the highest-performance option.

PSQL Parameters

With psql parameters you can format the output like CSV but there are downsides like having to remember to disable the pager and not getting headers:

$ psql -P pager=off -d mydb -t -A -F',' -c 'select * from groups;'
2,Technician,Test 2,,,t,,0,,                                                                                                                                                                   
3,Truck,1,2017-10-02,,t,,0,,                                                                                                                                                                   
4,Truck,2,2017-10-02,,t,,0,,

Other Tools

No, I just want to get CSV out of my server without compiling and/or installing a tool.

Answer 3

I had to use the \COPY because I received the error message:

ERROR:  could not open file "/filepath/places.csv" for writing: Permission denied

So I used:

\Copy (Select address, zip  From manjadata) To '/filepath/places.csv' With CSV;

and it is functioning

Answer 4

psql can do this for you:

edd@ron:~$ psql -d beancounter -t -A -F"," \
                -c "select date, symbol, day_close " \
                   "from stockprices where symbol like 'I%' " \
                   "and date >= '2009-10-02'"
2009-10-02,IBM,119.02
2009-10-02,IEF,92.77
2009-10-02,IEV,37.05
2009-10-02,IJH,66.18
2009-10-02,IJR,50.33
2009-10-02,ILF,42.24
2009-10-02,INTC,18.97
2009-10-02,IP,21.39
edd@ron:~$

See man psql for help on the options used here.

Answer 5

To Download CSV file with column names as HEADER use this command:

Copy (Select * From tableName) To '/tmp/fileName.csv' With CSV HEADER;

Answer 6

If you have longer query and you like to use psql then put your query to a file and use the following command:

psql -d my_db_name -t -A -F";" -f input-file.sql -o output-file.csv