Who are the officers involved in cases that are voted as 'No Bill'. List their last name and gender.
voted as 'No Bill' refers to grand_jury_disposition = 'No Bill'
SELECT T2.last_name, T2.gender FROM incidents AS T1 INNER JOIN officers AS T2 ON T1.case_number = T2.case_number WHERE T1.grand_jury_disposition = 'No Bill'
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)
);
