Initializing A Variable

Data Manipulation (DML) StatementsBuilt-in Scalar Functions

Initializing a Variable

Local variables are NULL when execution of the module begins.They can be explicitly initialized so that a starting or default value is available when they are first referenced.The initial value can be specified in two ways, DEFAULT <initvalue> and = <initvalue>.The value can be any type-compatible literal or context variable, including NULL.

Tip	Be sure to use this clause for any variables that have a `NOT NULL` constraint and do not otherwise have a default value available (i.e. inherited from a domain).

Examples of various ways to declare local variables

CREATE OR ALTER PROCEDURE SOME_PROC
AS
  -- Declaring a variable of the INT type
  DECLARE I INT;
  -- Declaring a variable of the INT type that does not allow NULL
  DECLARE VARIABLE J INT NOT NULL;
  -- Declaring a variable of the INT type with the default value of 0
  DECLARE VARIABLE K INT DEFAULT 0;
  -- Declaring a variable of the INT type with the default value of 1
  DECLARE VARIABLE L INT = 1;
  -- Declaring a variable based on the COUNTRYNAME domain
  DECLARE FARM_COUNTRY COUNTRYNAME;
  -- Declaring a variable of the type equal to the COUNTRYNAME domain
  DECLARE FROM_COUNTRY TYPE OF COUNTRYNAME;
  -- Declaring a variable with the type of the CAPITAL column in the COUNTRY table
  DECLARE CAPITAL TYPE OF COLUMN COUNTRY.CAPITAL;
BEGIN
  /* PSQL statements */
END