### Database Schema:
CREATE TABLE incidents (
	case_number	TEXT	NOT NULL	PRIMARY KEY,
	date	DATE	NOT NULL,
	location	TEXT	NOT NULL,
	subject_statuses	TEXT	NOT NULL,
	subject_weapon	TEXT	NOT NULL,
	subjects	TEXT	NOT NULL,
	subject_count	INTEGER	NOT NULL,
	officers	TEXT	NOT NULL
);

CREATE TABLE officers (
	case_number	TEXT	NOT NULL,
	race	TEXT	NULL,
	gender	TEXT	NOT NULL,
	last_name	TEXT	NOT NULL,
	first_name	TEXT	NULL,
	full_name	TEXT	NOT NULL,
	foreign key (case_number) references incidents (case_number)
);

CREATE TABLE subjects (
	case_number	TEXT	NOT NULL,
	race	TEXT	NOT NULL,
	gender	TEXT	NOT NULL,
	last_name	TEXT	NOT NULL,
	first_name	TEXT	NULL,
	full_name	TEXT	NOT NULL,
	foreign key (case_number) references incidents (case_number)
);

### User's Query:
Did the number of cases with Vehicle as subject weapon increase or decrease from year 2007 to 2008. State the difference.

### Extra Knowledge:
number of cases refers to count(case_number); with Vehicle as subject weapon refers to subject_weapon = 'Vehicle'; year 2007 refers to date between '2007-01-01' and '2007-12-31'; year 2008 refers to date between '2008-01-01' and '2008-12-31'
SELECT SUM(IIF(STRFTIME('%Y', date) = '2007', 1, 0)) - SUM(IIF(STRFTIME('%Y', date) = '2008', 1, 0)) FROM incidents WHERE subject_weapon = 'Vehicle'