### 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:
How many more black female victims than white female victims were discovered?

### Extra Knowledge:
black refers to race = 'B'; female refers to gender = 'F'; white refers to race = 'W'; result = subtract(count(victims where race = 'B'), count(victims where race = 'W')) where gender = 'F'
SELECT SUM(race = 'B') - SUM(race = 'W') FROM subjects WHERE gender = 'F'