Show the minimum amount of transactions whose type code is 'PUR' and whose share count is bigger than 50.
CREATE TABLE transactions_lots (
    transaction_id number,
    lot_id number
)

CREATE TABLE investors (
    investor_id number,
    investor_details text
)

CREATE TABLE lots (
    lot_id number,
    investor_id number,
    lot_details text
)

CREATE TABLE purchases (
    purchase_transaction_id number,
    purchase_details text
)

CREATE TABLE ref_transaction_types (
    transaction_type_code text,
    transaction_type_description text
)

CREATE TABLE sales (
    sales_transaction_id number,
    sales_details text
)

CREATE TABLE transactions (
    transaction_id number,
    investor_id number,
    transaction_type_code text,
    date_of_transaction time,
    amount_of_transaction number,
    share_count text,
    other_details text
)
SELECT MIN(amount_of_transaction) FROM transactions WHERE transaction_type_code = "PUR" AND share_count > 50
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: Show the minimum amount of transactions whose type code is 'PUR' and whose share count is bigger than 50. ### Input: CREATE TABLE transactions_lots (
    transaction_id number,
    lot_id number
)

CREATE TABLE investors (
    investor_id number,
    investor_details text
)

CREATE TABLE lots (
    lot_id number,
    investor_id number,
    lot_details text
)

CREATE TABLE purchases (
    purchase_transaction_id number,
    purchase_details text
)

CREATE TABLE ref_transaction_types (
    transaction_type_code text,
    transaction_type_description text
)

CREATE TABLE sales (
    sales_transaction_id number,
    sales_details text
)

CREATE TABLE transactions (
    transaction_id number,
    investor_id number,
    transaction_type_code text,
    date_of_transaction time,
    amount_of_transaction number,
    share_count text,
    other_details text
) ### Response: SELECT MIN(amount_of_transaction) FROM transactions WHERE transaction_type_code = "PUR" AND share_count > 50