Write five questions that can be answered from the data in your database (read the query code

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Question:

Write five questions that can be answered from the data in your database (read the query code requirements before writing your questions). Write query code to find answers to your questions. Your code must include the following: At least one union (justify why this was needed over a join). At least two joins. Provide an explanation of which type of join you used and why it was the best option. (POSTGRESQL)

CREATE TABLE flat_details ( flat_type varchar(30) NOT NULL, property_type varchar(10) NOT NULL, number_of_levels int NOT NULL, year date NOT NULL, flat_id varchar(40) NOT NULL, Seller_buyer varchar(30) NOT NULL, number_of_units varchar(30) NOT NULL, oneroom_flats_sold int NOT NULL, tworoom_flats_sold int NOT NULL, property_id int NOT NULL, threeroom_flats_sold int NOT NULL, fourroom_flats_sold int NOT NULL, multi_generationflats_sold int NOT NULL, fiveroom_flats_sold int NOT NULL, executiveroom_flats_sold int NOT NULL, studioapt_sold int NOT NULL, singleroom_rental int NOT NULL, doubleroom_rental int NOT NULL, tripleroom_rental int NOT NULL, multiroom_rental int NOT NULL, UNIQUE INDEX flat_details_ak_1 (property_id), CONSTRAINT flat_details_pk PRIMARY KEY (flat_id) ); INSERT INTO flat_details (flat_type, property_type, number_of_levels, Year, flat_id, seller_buyer, number_of_units, oneroom_flats_sold, tworoom_flats_sold, property_id, threeroom_flats_sold, fourroom_flats_sold, multi_generationflats_sold, fiveroom_flats_sold, executiveroom_flats_sold, studioapt_sold, singleroom_rental, doubleroom_rental, tripleroom_rental, multiroom_rental) VALUES (' 1-room flats', 'HDB', ' 40', ' 2019-12-31', ' TENANT', '2,160', '0', '1', '0', '0', '0', '0', '1', '1', '1', '1', '1', '1','1', '1');

CREATE TABLE hdb ( property_id varchar(30) NOT NULL, block_no varchar(30) NOT NULL, property_type varchar(10) NOT NULL, flat_type varchar(40) NOT NULL, number_of_levels int NOT NULL, carparking_levels boolean NOT NULL, town_legend varchar(30) NOT NULL, year date NOT NULL, sales_person varchar(30) NOT NULL, salesperson_name varchar(30) NOT NULL, flat_details_flat_id varchar(40) NOT NULL, hdb_salesdetails_salesperson_reg_num varchar(30) NOT NULL, property_flatdetails_flat_id varchar(40) NOT NULL, CONSTRAINT hdb_pk PRIMARY KEY (property_id) ); INSERT INTO hdb (property_id, block_no, property_type, flat_type, Number_of_levels, carparking_levels, town_legend, year, sales_person, salesperson_name, flat_details_flat_id, hdb_salesdetails_salesperson_reg_num, property_flatdetails_flat_id) VALUES ('2', '9B', 'HDB', 'Executive/Multi-Generation flats', '10', '4', 'BM', '2009-12-31', 'LANDLORD', ' ZOELYN LIM','221','33','22');

CREATE TABLE hdb_salesdetails ( salesperson_reg_num varchar(30) NOT NULL, transaction_date date NOT NULL, salesperson_name varchar(30) NOT NULL, transaction_type varchar(30) NOT NULL, seller_buyer varchar(30) NOT NULL, town varchar(30) NOT NULL, district int NOT NULL, general_location varchar(60) NOT NULL, flat_details_flat_id varchar(40) NOT NULL, UNIQUE INDEX hdb_salesdetails_ak_1 (salesperson_name), CONSTRAINT hdb_salesdetails_pk PRIMARY KEY (salesperson_reg_num)

); INSERT INTO hdb_salesdetails (salesperson_reg_num, transaction_date, salesperson_name, transaction_type, seller_buyer, town, district, general_location, Flat_details_flat_id) VALUES (' R044210D', '2007-12-31', ' ZHUO DAWEI', ' RESALE', 'seller', ' TP', '10', ' JURONG', '1');

CREATE TABLE property_flatdetails ( flat_id varchar(40) NOT NULL, property_type varchar(40) NOT NULL, status_sold_rented varchar(30) NOT NULL, number_of_units int NOT NULL, flat_type varchar(40) NOT NULL, number_of_units_sold int NOT NULL, number_of_units_rented int NOT NULL, residential_property boolean NOT NULL, commercial_property boolean NOT NULL, Flat_details_flat_id varchar(40) NOT NULL, UNIQUE INDEX property_flatdetails_ak_1 (flat_type), CONSTRAINT property_flatdetails_pk PRIMARY KEY (flat_id) ); INSERT INTO property_flatdetails (flat_id, property_type, status_sold_rented, number_of_units, flat_type, number_of_units_sold, number_of_units_rented, residential_property, commercial_property, Flat_details_flat_id) VALUES ('1', ' 5-room flats', 'Rented', '5', ' CONDOMINIUM_APARTMENTS', '1', '0', '1', '0', '1');

Please respond in POSTGRESQL coding language. Please explain briefly.