Dynamic SQL PostgreSQL

I want to know the basics of dynamic sql especially in PostgreSQL. I was googling for a while but have no luck for getting a good described examples. Maybe someone here could give me some links to the materials from which you where studying this subject.

Ok so to be more accurate I am interested in examples of especially PL/SQL (PostgreSQL) code which will demonstrat开发者_运维知识库e examples with description :)

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Here is a good place to start: http://www.postgresql.org/docs/9.1/static/plpgsql-statements.html#PLPGSQL-STATEMENTS-SQL-NORESULT

Look in particular at section called "Executing Dynamic Commands".