The following syntax is used to declare how error handlers handle exceptions when they occur. 
DECLARE [UNDO | CONTINUE | EXIT] HANDLER FOR [SQLEXCEPTION | SQLWARNING | NOT FOUND
SQLSTATE <sql_state>[, ...]] [<procedural_statement>]

where:

UNDO
specifies that all the changes made inside the block are undone before executing the statement after the block, if any.
CONTINUE
specifies that the exception is ignored, then the next iteration or statement after the block, if any, is executed.
EXIT
specifies that the block is terminated, but any successful changes are preserved.
SQLEXCEPTION
specifies that the procedural statement is to be executed when a SQL exception is encountered.
SQLWARNING
specifies that procedural statement to be executed when a SQL warning is encountered.
NOT FOUND
specifies that the procedural statement is to be executed when a DELETE, UPDATE, INSERT, or MERGE statement is executed without affecting any rows.
SQLSTATE
specifies that the procedural statement is to be executed when the specified SQLSTATE code is encountered.
sql_state
specifies the five-character SQLSTATE code. For example, HY000.
procedural_statement
(optional) specifies the procedural statement to be executed when the conditions in the declaration are encountered.