diff --git a/README.md b/README.md
index 0d20bee..715e580 100644
--- a/README.md
+++ b/README.md
@@ -13,6 +13,9 @@ Pull requests are welcome. Enjoy!
5. [ View Queries. ](#view)
6. [ Altering Table Queries.](#alter)
7. [ Creating Table Query.](#create)
+8. [Advanced SQL Functions](#advanced)
+9. [Common SQL Patterns](#patterns)
+
# 1. Finding Data Queries
@@ -193,3 +196,69 @@ Pull requests are welcome. Enjoy!
`column3` `datatype`,
`column4` `datatype`,
`);`
+
+
+
+
+## 8. Advanced SQL Functions
+
+### **CASE Statement**: Adds conditional logic to queries.
+```sql
+SELECT CASE WHEN condition THEN result_1 ELSE result_2 END AS alias_column FROM your_table;
+-- Example:
+SELECT employee_id,
+ CASE WHEN salary > 50000 THEN 'High' ELSE 'Low' END AS salary_level
+FROM employees;
+```
+
+### **COALESCE() Function**: Returns the first non-null value in the list.
+```sql
+SELECT COALESCE(column_1, 'default_value') AS result_column FROM your_table;
+-- Example:
+SELECT employee_id, COALESCE(bonus, 0) AS bonus_amount FROM employees;
+```
+
+### **STRING_AGG() Function (PostgreSQL)**: Concatenates values from multiple rows into one string.
+```sql
+SELECT STRING_AGG(column_value, ', ') AS concatenated_values FROM your_table GROUP BY grouping_column;
+-- Example:
+SELECT department_id, STRING_AGG(employee_id::text, ', ') AS employees_list FROM employees GROUP BY department_id;
+```
+---
+
+
+## 9. Common SQL Patterns
+
+These patterns can help you solve frequent tasks in SQL.
+
+- ### Pagination:
+ ```sql
+ SELECT * FROM your_table ORDER BY id LIMIT page_size OFFSET (page_number - 1) * page_size;
+ ```
+
+- ### Find Duplicates:
+ ```sql
+ SELECT column_to_check, COUNT(*) as count
+ FROM your_table GROUP BY column_to_check HAVING COUNT(*) > 1;
+ ```
+
+- ### Conditional Aggregation:
+ ```sql
+ SELECT department,
+ SUM(CASE WHEN gender = 'M' THEN salary ELSE 0 END) AS male_salary,
+ SUM(CASE WHEN gender = 'F' THEN salary ELSE 0 END) AS female_salary
+ FROM employees GROUP BY department;
+ ```
+
+- ### Recursive Query for Hierarchical Data:
+ ```sql
+ WITH RECURSIVE hierarchy AS (
+ SELECT id, parent_id, name FROM categories WHERE parent_id IS NULL -- Starting point for recursion
+ UNION ALL
+ SELECT c.id, c.parent_id, c.name
+ FROM categories c
+ INNER JOIN hierarchy h ON h.id = c.parent_id
+ )
+ SELECT * FROM hierarchy;
+ ```
+