How to add a line break to PostgreSQL?

You have to insert some data into your PostgreSQL table that has line break. As a result, the cell will look like this:

First line
Second line

To use "escape sequences" in a string literal you need to use an "extended" constant. You can specify the escape character by prefixing the letter E:

UPDATE posts SET body = E'First Line\nSecond line.' WHERE id = 2701;