MySQL 8.4 Release Notes
SIGNAL,
RESIGNAL, and
GET DIAGNOSTICS are not permissible
as prepared statements. For example, this statement is invalid:
PREPARE stmt1 FROM 'SIGNAL SQLSTATE "02000"';
SQLSTATE values in class
'04' are not treated specially. They are
handled the same as other exceptions.
In standard SQL, the first condition relates to the
SQLSTATE value returned for the previous SQL
statement. In MySQL, this is not guaranteed, so to get the main
error, you cannot do this:
GET DIAGNOSTICS CONDITION 1 @errno = MYSQL_ERRNO;Instead, do this:
GET DIAGNOSTICS @cno = NUMBER;
GET DIAGNOSTICS CONDITION @cno @errno = MYSQL_ERRNO;