declare and set sql variable code example

Example 1: declare value in sql

DECLARE  { @LOCAL_VARIABLE[AS] data_type  [ = value ] }

Example 2: local variables in sql

Local variables:
These variables can be used or exist 
only inside the function. These variables
are not used or referred by any other function.

Global variables:
These variables are the variables which
can be accessed throughout the program.
Global variables cannot be created
whenever that function is called.