Upsert data from CSV to PostgreSQL table via command line on Windows

Want to upsert data from CSV file to existing PostgreSQL table via command line on Windows?

Using pg-cmd, a Command-Line client for PostgreSQL, you can upsert(merge) CSV/TSV/TXT data to PostgreSQL table easily and fast.

Support Windows, Linux, and MacOS.

Download pg-cmd Windows version
pg-cmd.windows-386.zip
pg-cmd.windows-amd64.zip

No need to install PostgreSQL client library.

Convenient to deploy to cloud. No need to run installation file, just uncompress and run, immediately.

Upsert/Merge CSV/TSV/TXT data into PostgreSQL table via command line on Windows

1. In interactive mode:

pg-cmd> load loadtype=upsert
      > updatekey=id
      > table=media_messages 
      > datafile=f:\media_messages.csv 
      > delimiter=, 
      > quote=" 
      > header=y;

2. In batch mode:

pg-cmd dsn="pan:withdata@192.168.0.102/test" task=load loadtype=upsert updatekey=id table=media_messages datafile=f:\media_messages.csv delimiter=, quote=" header=y quit=y

“loadtype=upsert” will update row in table if “updatekey” id exists, or insert new row.

See parameters detail.

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More about pg-cmd – Command-Line client for PostgreSQL

CSV → PostgreSQL reference

Type mapping

Value kind	in CSV	in PostgreSQL
Int	1234	integer
Bigint	9007199254740993	bigint
Decimal	1234.56	numeric(p,s)
Float	1.234e+10	double precision
Text	quoted only when it contains a comma or a quote	varchar(n)
Long text	must be quoted; line breaks inside force multi-line records	text
Date	2026-09-18	date
Datetime	2026-09-18 14:30:00	timestamp
Binary	not representable - base64 or hex string	bytea
Boolean	TRUE / FALSE, or 1 / 0 depending on the writer	boolean
JSON	the whole JSON value quoted, with internal quotes doubled	jsonb

Dialect differences

CSV is a file format and PostgreSQL is a database server, so the target has to be told the types the file never carried - the rows below are where the two sides diverge.

Property	in CSV	in PostgreSQL
port	—	5432
identifiers	Double quotes; a literal quote is doubled ("" )	"double quotes"
row limit	—	LIMIT n
dates	Conventional text: 2026-09-18 or 2026-09-18 14:30:00	timestamp, timestamptz, date, time
long text	—	TEXT
binary	Not supported	BYTEA
separator	Comma ","	—
encoding	No declaration - UTF-8 works only with a BOM	—
typing	None - every field is text	—
shape	Flat table, optional header row	Tables of rows and columns
ceiling	No formal limit; row count bounded by memory	—

Command line

Side	Command
PostgreSQL	pg_dump or COPY ... TO
PostgreSQL (load)	COPY ... FROM

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