SQL script to create insert script

Question

A bit of a vague title, I will explain.

I am writing an SQL script to create an insert statement for each row of a table in my database, purely to be able to apply that

Answer 1

I wrote a python script based on @intgr answer to construct the select statement. It takes comma separated list of columns from stdin (use -).

I wanted to use sqlparse but I couldn't understand how to use that lib.

import fileinput

names = ' '.join(fileinput.input())

ns = [x.strip() for x in names.split(',')]
quoted = ['quote_nullable(' + x + ')' for x in ns]
insert = "SELECT  'INSERT INTO <TABLE> ( " + (', ').join(ns) + " ) VALUES(' || " + (" || ',' || ").join(quoted)  + " || ');' FROM <TABLE>"
print insert

A gist of the script is here: https://gist.github.com/2568047

Answer 2

Use the quote_nullable() function new in PostgreSQL 8.4. In addition to permitting NULL values, it retains your data types and protects you from Bobby Tables (SQL injections):

SELECT 'INSERT INTO products (id,name,description) VALUES (' ||
quote_nullable(ID) || ',' || quote_nullable(name) || ',' ||
quote_nullable(description) || ');' FROM products;

In older versions, you get the same behavior with coalesce() and quote_literal():

SELECT 'INSERT INTO products (id,name,description) VALUES (' ||
coalesce(quote_literal(ID), 'null') || ',' ||
coalesce(quote_literal(name), 'null') || ',' ||
coalesce(quote_literal(description), 'null') || ',' ||
');' FROM products;

Answer 3

In the case of NULL fields you can do something like

Select COALESCE(Name, '') from...

The coalesce function returns the first nonnull value in the list.

For truly blank fields (empty nvarchar for instance) I believe your script above will work.

Answer 4

pg_dump -a -U user1 -t products -f products.copy database1

and then:

psql -U user2 -d database2 -f products.copy

and you're done. It's also safer and faster.