How many different items were reviewed by some users?
CREATE TABLE review (
    a_id number,
    u_id number,
    i_id number,
    rating number,
    rank number
)

CREATE TABLE item (
    i_id number,
    title text
)

CREATE TABLE useracct (
    u_id number,
    name text
)

CREATE TABLE trust (
    source_u_id number,
    target_u_id number,
    trust number
)
SELECT COUNT(DISTINCT i_id) FROM review
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: How many different items were reviewed by some users? ### Input: CREATE TABLE review (
    a_id number,
    u_id number,
    i_id number,
    rating number,
    rank number
)

CREATE TABLE item (
    i_id number,
    title text
)

CREATE TABLE useracct (
    u_id number,
    name text
)

CREATE TABLE trust (
    source_u_id number,
    target_u_id number,
    trust number
) ### Response: SELECT COUNT(DISTINCT i_id) FROM review