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 queries from.
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 queries from.
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
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!
Yes I did, here are my notes:
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.
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,,
No, I just want to get CSV out of my server without compiling and/or installing a tool.
New version - psql 12 - will support --csv.
--csv
Switches to CSV (Comma-Separated Values) output mode. This is equivalent to \pset format csv.
csv_fieldsep
Specifies the field separator to be used in CSV output format. If the separator character appears in a field's value, that field is output within double quotes, following standard CSV rules. The default is a comma.
Usage:
psql -c "SELECT * FROM pg_catalog.pg_tables" --csv postgres
psql -c "SELECT * FROM pg_catalog.pg_tables" --csv -P csv_fieldsep='^' postgres
psql -c "SELECT * FROM pg_catalog.pg_tables" --csv postgres > output.csv
To Download CSV file with column names as HEADER use this command:
Copy (Select * From tableName) To '/tmp/fileName.csv' With CSV HEADER;
Per the request of @skeller88, I am reposting my comment as an answer so that it doesn't get lost by people who don't read every response...
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