Getting two issues while using stored procedure in MySQL

Question

Below is the sample code of my Stored Procedure in which I am working on for interest calculation. This code is not executable because according to finding its getting issue whi

Answer 1

DECLARE is permitted only inside a BEGIN ... END compound statement and must be at its start, before any other statements.

Declarations must follow a certain order. Cursor declarations must appear before handler declarations. Variable and condition declarations must appear before cursor or handler declarations.

http://dev.mysql.com/doc/refman/5.7/en/declare.html

That's the restriction.

Now, the workaround: add a nested BEGIN ... END block.

DELIMITER $$
CREATE PROCEDURE ...
BEGIN
  DECLARE ... INT ... -- variable
  CREATE TEMPORARY TABLE... -- following the declarations, no more declarations allowed, unless...
  BEGIN -- resets the scope, changes the rules, allows more declarations
    DECLARE ... INT ... -- variables
    DECLARE ... CURSOR ...
    DECLARE CONTINUE HANDLER ...
    OPEN ...
    ...
  END;
END $$

All the variables in the outer block are still in scope in the inner block, unless another variable in the inner block has a conflicting name.

A HANDLER in the outer block is also in scope for signals in the inner block, unless a conflicting handler is declared there, in which case the inner handler will catch the exception and the outer handle will catch anything throw by the inner handler, including a RESIGNAL.

Multiple nesting levels are allowed. The size of the thread_stack might be a factor, but the documentation is unclear. I've been running 262,144 byte thread stacks since before it was made the default, and have never encountered a limit.