MySQL CREATE a stored procedure detailed instance tutorial (1/9)

Create a stored procedure in the mysql tutorial
"Pr_add" is a simple mysql stored procedure, which has two int-type input parameters: "a" and "B", and returns the sum of the two parameters.

Drop procedure if exists pr_add;

-- Calculate the sum of two numbers

Create procedure pr_add
(
A int,
B int
)
Begin
Declare c int;

If a is null then
Set a = 0;
End if;

If B is null then
Set B = 0;
End if;

Set c = a B;

Select c as sum;

/*
Return c; -- cannot be used in mysql stored procedures. Return can only appear in functions.
*/
End;
Ii. Call the mysql Stored Procedure
Call pr_add (10, 20 );
Execute the mysql stored procedure. The stored procedure parameter is a mysql user variable.

Set @ a = 10;
Set @ B = 20; 1 2 3 4 5 6 7 8 9