The structure of PL/pgSQL is fairly simple, mainly due to the fact that each portion of code is designed to exist as a function. While it may not look immediately similar to other languages, PL/pgSQL’s structure is similar to other programming languages such as C, in which each portion of code acts (and is created) as a function, all variables must be declared before being used, and code segments accept arguments when called and return arguments at their end.
Regarding its syntax, PL/pgSQL functions are case insensitive. You can use mixed, upper-,
or lowercase for keywords and identifiers. Additionally, you will notice the use of pairs of
apostrophes (single quotes) in many places within this chapter. These are required whenever a
single apostrophe would ordinarily be used. The pair of apostrophes is a means to escape an
apostrophe within the function definition to PostgreSQL, since a function definition is
actually a large string constant within a
CREATE FUNCTION statement.
This section will discuss the block organization of PL/pgSQL code, how to use comments, how PL/pgSQL expressions are organized, and the usage of statements.
PL/pgSQL code is organized in blocks of code. This method of organization is known as
block structured code. Code blocks are entered within a SQL
CREATE FUNCTION call that creates the PL/pgSQL function in the PostgreSQL
CREATE FUNCTION command names the new function, states its argument types, and states the return ...