・If the value of the expression specified by WHEN and the value of the expression specified by CASE are the same, jump to the next command after WHEN, and jump to the next WHEN or OTHERWISE if the values are different.
・When jumping to the next command to WHEN, jumps to ENDCASE when executed until just before the next WHEN.
・When WHEN is written continuously, it is treated as a group.
・In other words, when WHEN A:WHEN B is written, it means "when CASE value is A or B".
・It can only be used within CASE to ENDCASE.
Expression that becomes a branch condition