Solutions:

1.
SELECT p.SKU_Code, p.Design_No, pr.TP_Price, pr.Final_MRP
FROM Pricing pr
LEFT JOIN Products p ON pr.SKU_Code = p.SKU_Code;

2.
SELECT w.Operation_ID, w.SKU_Code, p.Design_No, w.Operation_Type
FROM Warehouse_Ops w
LEFT JOIN Products p ON w.SKU_Code = p.SKU_Code;

3.
SELECT COALESCE(i.SKU_Code, p.SKU_Code) AS SKU_Code
FROM Inventory i
FULL OUTER JOIN Pricing p ON i.SKU_Code = p.SKU_Code
WHERE i.SKU_Code IS NULL OR p.SKU_Code IS NULL;

4.
SELECT c.Customer_ID, c.Customer_Name, p.SKU_Code, p.Design_No
FROM Customers c
CROSS JOIN Products p;

5.
SELECT p1.SKU_Code, p1.Category, p2.Category AS Parent_Category
FROM Products p1
LEFT JOIN Products p2 ON p1.Category LIKE CONCAT(p2.Category, '%') 
AND p1.Category != p2.Category;

6.
SELECT COALESCE(i.SKU_Code, p.SKU_Code) AS SKU_Code, 
       i.Stock_Qty, p.TP_Price
FROM Inventory i
FULL OUTER JOIN Pricing p ON i.SKU_Code = p.SKU_Code;

7.
SELECT c.Customer_ID, c.Customer_Name, s.SKU_Code, COUNT(*) AS Purchase_Count
FROM Customers c
JOIN Sales_Transactions s ON c.Customer_ID = s.Customer_ID
GROUP BY c.Customer_ID, c.Customer_Name, s.SKU_Code
HAVING COUNT(*) > 1;

8.
SELECT SKU_Code, Weight, Color
FROM Products
WHERE Weight IS NULL OR Color IS NULL;

9.
SELECT DISTINCT p1.Size, p2.Color
FROM Products p1
CROSS JOIN Products p2;

10.
SELECT a.SKU_Code AS Product_SKU, a.Design_No AS Product_Design,
       b.SKU_Code AS Pair_SKU, b.Design_No AS Pair_Design
FROM Products a
JOIN Products b ON a.Category = b.Category AND a.SKU_Code < b.SKU_Code;

11.
WITH CustomerCategories AS (
  SELECT c.Customer_ID, p.Category
  FROM Customers c
  CROSS JOIN (SELECT DISTINCT Category FROM Products) p
)
SELECT cc.Customer_ID, c.Customer_Name, cc.Category AS Missing_Categories
FROM CustomerCategories cc
JOIN Customers c ON cc.Customer_ID = c.Customer_ID
LEFT JOIN (
  SELECT s.Customer_ID, p.Category
  FROM Sales_Transactions s
  JOIN Products p ON s.SKU_Code = p.SKU_Code
) pc ON cc.Customer_ID = pc.Customer_ID AND cc.Category = pc.Category
WHERE pc.Category IS NULL;

12.
SELECT p.SKU_Code,
       CASE WHEN s.SKU_Code IS NOT NULL THEN 'Yes' ELSE 'No' END AS Has_Sales,
       CASE WHEN i.SKU_Code IS NOT NULL THEN 'Yes' ELSE 'No' END AS In_Inventory
FROM Products p
LEFT JOIN Sales_Transactions s ON p.SKU_Code = s.SKU_Code
LEFT JOIN Inventory i ON p.SKU_Code = i.SKU_Code;

13.
SELECT SKU_Code, MIN(Quantity) AS Consistent_Quantity
FROM Sales_Transactions
GROUP BY SKU_Code
HAVING MIN(Quantity) = MAX(Quantity);

14.
WITH RECURSIVE CategoryHierarchy AS (
  SELECT Category, NULL AS Parent_Category, 1 AS Hierarchy_Level
  FROM Products
  WHERE Category NOT LIKE '%-%'
  
  UNION ALL
  
  SELECT p.Category, 
         SUBSTRING(p.Category, 1, INSTR(p.Category, '-')-1) AS Parent_Category,
         ch.Hierarchy_Level + 1
  FROM Products p
  JOIN CategoryHierarchy ch ON p.Category LIKE CONCAT(ch.Category, '-%')
)
SELECT * FROM CategoryHierarchy;

15.
SELECT c.Customer_ID, p.SKU_Code,
       CASE WHEN s.Sale_ID IS NOT NULL THEN 'Yes' ELSE 'No' END AS Has_Purchased
FROM Customers c
CROSS JOIN Products p
LEFT JOIN Sales_Transactions s ON c.Customer_ID = s.Customer_ID AND p.SKU_Code = s.SKU_Code;