MySQL 5.6 Reference Manual Including MySQL NDB Cluster 7.3-7.4 Reference Guide
If a stored procedure exits with an unhandled exception,
modified values of OUT
and
INOUT
parameters are not propogated back to
the caller.
If an exception is handled by a CONTINUE
or
EXIT
handler that contains a
RESIGNAL
statement, execution of
RESIGNAL
pops the Diagnostics
Area stack, thus signalling the exception (that is, the
information that existed before entry into the handler). If the
exception is an error, the values of OUT
and
INOUT
parameters are not propogated back to
the caller.