Solutions:

1.
UPDATE Products 
SET Weight = Weight + 0.1
WHERE Category = 'Men'
RETURNING SKU_Code, Weight;

2.
INSERT INTO Customers (Customer_ID, Customer_Name, Email, Phone)
VALUES ('CUST016', 'RAJIV MEHTA', 'rajiv@example.com', '+919876543225')
RETURNING *;

3.
DELETE FROM Sales_Transactions
WHERE Date < CURRENT_DATE - INTERVAL '2 years'
RETURNING *;

4.
UPDATE Pricing p
SET TP_Price = TP_Price * 1.10
FROM (
  SELECT SKU_Code, AVG(Gross_Amount) as avg_sales
  FROM Sales_Transactions
  GROUP BY SKU_Code
) s
WHERE p.SKU_Code = s.SKU_Code 
AND s.avg_sales < (SELECT AVG(Gross_Amount) FROM Sales_Transactions)
RETURNING p.SKU_Code, p.TP_Price;

5.
BEGIN TRANSACTION;

INSERT INTO Warehouse_Ops (Operation_Type, SKU_Code, Quantity, Date)
VALUES 
  ('Inbound', 'Os206_3141_S', 25, CURRENT_DATE),
  ('Outbound', 'MEN5004-KR-L', 10, CURRENT_DATE),
  ('Inbound', 'WOM2022-S', 15, CURRENT_DATE);

COMMIT;

SELECT * FROM Warehouse_Ops WHERE Date = CURRENT_DATE;

6.
DELETE FROM Products
WHERE SKU_Code NOT IN (SELECT DISTINCT SKU_Code FROM Sales_Transactions)
AND SKU_Code NOT IN (SELECT DISTINCT SKU_Code FROM Inventory)
RETURNING *;

7.
UPDATE Customers c
SET Customer_Name = UPPER(Customer_Name)
FROM (
  SELECT Customer_ID, SUM(Gross_Amount) as total_spent
  FROM Sales_Transactions
  GROUP BY Customer_ID
  HAVING SUM(Gross_Amount) > 5000
) s
WHERE c.Customer_ID = s.Customer_ID
RETURNING c.Customer_ID, c.Customer_Name;

8.
INSERT INTO Sales_Transactions (Sale_ID, Customer_ID, SKU_Code, Quantity, Rate, Gross_Amount, Date)
SELECT Sale_ID, Customer_ID, SKU_Code, Quantity, Rate, Gross_Amount, Date
FROM Sales_Staging
WHERE NOT EXISTS (
  SELECT 1 FROM Sales_Transactions st 
  WHERE st.Sale_ID = Sales_Staging.Sale_ID
)
RETURNING *;

9.
WITH Duplicates AS (
  SELECT Operation_ID,
         ROW_NUMBER() OVER (PARTITION BY Operation_Type, SKU_Code, Quantity, Date 
                            ORDER BY Operation_ID DESC) as rn
  FROM Warehouse_Ops
)
DELETE FROM Warehouse_Ops
WHERE Operation_ID IN (
  SELECT Operation_ID FROM Duplicates WHERE rn > 1
)
RETURNING *;

10.
BEGIN TRANSACTION;

UPDATE Inventory i
SET Stock_Qty = i.Stock_Qty - w.Quantity
FROM Warehouse_Ops w
WHERE i.SKU_Code = w.SKU_Code 
AND w.Operation_Type = 'Outbound'
AND w.Date = CURRENT_DATE;

COMMIT;

SELECT * FROM Inventory WHERE SKU_Code IN (
  SELECT SKU_Code FROM Warehouse_Ops 
  WHERE Operation_Type = 'Outbound' AND Date = CURRENT_DATE
);

11.
INSERT INTO Products (SKU_Code, Design_No, Category, Size, Color, Weight, Catalog)
SELECT SKU_Code, Design_No, Category, Size, Color, Weight, Catalog
FROM Supplier_Feed
ON CONFLICT (SKU_Code) 
DO UPDATE SET
  Design_No = EXCLUDED.Design_No,
  Category = EXCLUDED.Category,
  Size = EXCLUDED.Size,
  Color = EXCLUDED.Color,
  Weight = EXCLUDED.Weight,
  Catalog = EXCLUDED.Catalog
RETURNING *;

12.
DELETE FROM Customers
WHERE Customer_ID NOT IN (
  SELECT DISTINCT Customer_ID
  FROM Sales_Transactions
  WHERE Date >= CURRENT_DATE - INTERVAL '365 days'
)
RETURNING *;

13.
BEGIN TRANSACTION;

UPDATE Sales_Transactions s
SET Gross_Amount = s.Gross_Amount * e.Exchange_Rate
FROM Exchange_Rates e
WHERE s.Date = e.Rate_Date
AND e.Currency = 'USD';

ROLLBACK; -- For demonstration, use COMMIT in production

SELECT * FROM Sales_Transactions 
WHERE Date IN (SELECT Rate_Date FROM Exchange_Rates);

14.
INSERT INTO Inventory (SKU_Code, Stock_Qty)
SELECT p.SKU_Code, 0
FROM Products p
WHERE p.SKU_Code NOT IN (SELECT SKU_Code FROM Inventory)
RETURNING *;

15.
BEGIN TRANSACTION;

-- Archive old records
INSERT INTO Sales_History
SELECT * FROM Sales_Transactions
WHERE Date < CURRENT_DATE - INTERVAL '1 year';

-- Delete archived records
DELETE FROM Sales_Transactions
WHERE Date < CURRENT_DATE - INTERVAL '1 year'
RETURNING *;

COMMIT;