An American rapper '2Pac' released his first solo album in 1991, how many years have passed until his next album was released?
2Pac is an artist; album refers to releaseType; groupYear = 1991; SUBTRACT(groupYear = 1991, groupYear where releaseType = 'album' LIMIT 1 OFFSET 1);
SELECT ( SELECT groupYear FROM torrents WHERE artist LIKE '2Pac' AND releaseType LIKE 'album' ORDER BY groupYear LIMIT 1, 1 ) - groupYear FROM torrents WHERE artist LIKE '2Pac' AND releaseType LIKE 'album' AND groupYear = 1991
CREATE TABLE IF NOT EXISTS "torrents"
(
    groupName     TEXT,
    totalSnatched INTEGER,
    artist        TEXT,
    groupYear     INTEGER,
    releaseType   TEXT,
    groupId       INTEGER,
    id            INTEGER
        constraint torrents_pk
            primary key
);
CREATE TABLE IF NOT EXISTS "tags"
(
    "index" INTEGER
        constraint tags_pk
            primary key,
    id      INTEGER
        constraint tags_torrents_id_fk
            references torrents,
    tag     TEXT
);
CREATE INDEX ix_tags_index
    on tags ("index");
