在过程中执行truncate table总是报语法错误

源代码如下：

BEGIN

DECLARE i INT;
DECLARE time_1 datetime;
DECLARE ID_1 int;
DECLARE charge_1 FLOAT;
DECLARE length_1 FLOAT;
DECLARE err_1 FLOAT;
DECLARE RSSI_1 FLOAT;
DECLARE stopflag INT DEFAULT 0;

TRUNCATE TABLE 220_1_copy;

DECLARE mycursor CURSOR FOR SELECT time,ID,charge,length,err,RSSI FROM 220_1 WHERE index_1 <100;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET stopflag=1;


OPEN mycursor;
REPEAT
    FETCH mycursor INTO time_1,ID_1,charge_1,length_1,err_1,RSSI_1;
    INSERT INTO 220_1_copy SET time=time_1,ID=ID_1,charge=charge_1,length=length_1,err=err_1,RSSI=RSSI_1;
    UNTIL stopflag=1 END REPEAT;
CLOSE mycursor;
END

保存代码提示：

改变红色代码 truncate table的位置就没事了如下：

BEGIN
    #Routine body goes here..
DECLARE i INT;
DECLARE time_1 datetime;
DECLARE ID_1 int;
DECLARE charge_1 FLOAT;
DECLARE length_1 FLOAT;
DECLARE err_1 FLOAT;
DECLARE RSSI_1 FLOAT;
DECLARE stopflag INT DEFAULT 0;


DECLARE mycursor CURSOR FOR SELECT time,ID,charge,length,err,RSSI FROM 220_1 WHERE index_1 <100;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET stopflag=1;

TRUNCATE TABLE 220_1_copy;

OPEN mycursor;
REPEAT
    FETCH mycursor INTO time_1,ID_1,charge_1,length_1,err_1,RSSI_1;
    INSERT INTO 220_1_copy SET time=time_1,ID=ID_1,charge=charge_1,length=length_1,err=err_1,RSSI=RSSI_1;
    UNTIL stopflag=1 END REPEAT;
CLOSE mycursor;
END

不知道为啥！！！