使用定义的变量，不能和字段名称一样包括大小写

下面的定义的变量中 ID CAR_CODE就是错误的，出现的情况是无法读取值

错误

BEGIN
    DECLARE GPS_ID VARCHAR(255) DEFAULT('');
    DECLARE ID VARCHAR(255) DEFAULT('');
    DECLARE CAR_CODE VARCHAR(255) DEFAULT('');
    DECLARE iCursor CURSOR FOR SELECT id,car_code FROM table where  state=0 and trans_type=0;
    DECLARE CONTINUE HANDLER FOR SQLSTATE '02000' SET CAR_CODE = NULL;
    OPEN iCursor;
    FETCH iCursor INTO ID,CAR_CODE;
    WHILE (CAR_CODE IS NOT NULL) DO
        SELECT gps_id INTO GPSID FROM table WHERE car_code = CAR_CODE;
        UPDATE table SET cache_key=CONCAT('finish_',GPS_ID) WHERE id=ID;
        FETCH iCursor INTO ID,CAR_CODE;
    END WHILE;
    CLOSE iCursor;
    
END

正确

BEGIN
    DECLARE TEMP_GPS_ID VARCHAR(255) DEFAULT('');
    DECLARE TEMP_ID VARCHAR(255) DEFAULT('');
    DECLARE TEMP_CAR_CODE VARCHAR(255) DEFAULT('');
    DECLARE iCursor CURSOR FOR SELECT id,car_code FROM table where  state=0 and trans_type=0;
    DECLARE CONTINUE HANDLER FOR SQLSTATE '02000' SET TEMP_CAR_CODE = NULL;
    OPEN iCursor;
    FETCH iCursor INTO TEMP_ID,TEMP_CAR_CODE;
    WHILE (TEMP_CAR_CODE IS NOT NULL) DO
        SELECT gps_id INTO TEMP_GPSID FROM table WHERE car_code = TEMP_CAR_CODE;
        UPDATE table SET cache_key=CONCAT('finish_',TEMP_GPS_ID) WHERE id=TEMP_ID;
        FETCH iCursor INTO TEMP_ID,TEMP_CAR_CODE;
    END WHILE;
    CLOSE iCursor;
    
END