MySQL 8.4 Release Notes
FETCH [[NEXT] FROM] cursor_name INTO var_name [, var_name] ...
This statement fetches the next row for the
SELECT statement associated with
the specified cursor (which must be open), and advances the
cursor pointer. If a row exists, the fetched columns are stored
in the named variables. The number of columns retrieved by the
SELECT statement must match the
number of output variables specified in the
FETCH statement.
If no more rows are available, a No Data condition occurs with
SQLSTATE value '02000'. To detect this
condition, you can set up a handler for it (or for a
NOT FOUND condition). For an example, see
Section 15.6.6, “Cursors”.
Be aware that another operation, such as a
SELECT or another FETCH,
may also cause the handler to execute by raising the same
condition. If it is necessary to distinguish which operation
raised the condition, place the operation within its own
BEGIN ...
END block so that it can be associated with its own
handler.