SQL Virus Using Quines for PostgreSQL

PostgreSQL does not support variables. A function is created instead. After the virus has replicated itself, the function is dropped, otherwise an error will be generated the next time the virus executes.

Strings are handled differently on PostgreSQL. PostgreSQL uses two single quotes ('') to escape a quote rather than the \' MySQL uses. It also does not provide the concat function, but uses the concatenation operator || instead.

On PostgreSQL, the function quote_literal is used to escape strings. This is similar to the QUOTE function on MySQL.
Due to the use of the function, the string must be escaped twice. This causes two sets of quotes to be added around the string. The first set of quotes that are added are stripped off, using the trim function.