What is the sum of revenue from companies with headquarters in Austin?
CREATE TABLE manufacturers (
    code number,
    name text,
    headquarter text,
    founder text,
    revenue number
)

CREATE TABLE products (
    code number,
    name text,
    price number,
    manufacturer number
)
SELECT SUM(revenue) FROM manufacturers WHERE headquarter = 'Austin'
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 is the sum of revenue from companies with headquarters in Austin? ### Input: CREATE TABLE manufacturers (
    code number,
    name text,
    headquarter text,
    founder text,
    revenue number
)

CREATE TABLE products (
    code number,
    name text,
    price number,
    manufacturer number
) ### Response: SELECT SUM(revenue) FROM manufacturers WHERE headquarter = 'Austin'