What are the names of all directors who have made one movie except for the director named NULL?
CREATE TABLE movie (
    mid number,
    title text,
    year number,
    director text
)

CREATE TABLE reviewer (
    rid number,
    name text
)

CREATE TABLE rating (
    rid number,
    mid number,
    stars number,
    ratingdate time
)
SELECT director FROM movie WHERE director <> "null" GROUP BY director HAVING COUNT(*) = 1
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: What are the names of all directors who have made one movie except for the director named NULL? ### Input: CREATE TABLE movie (
    mid number,
    title text,
    year number,
    director text
)

CREATE TABLE reviewer (
    rid number,
    name text
)

CREATE TABLE rating (
    rid number,
    mid number,
    stars number,
    ratingdate time
) ### Response: SELECT director FROM movie WHERE director <> "null" GROUP BY director HAVING COUNT(*) = 1