A Beginner's Handbook to SQL Operators

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SQL (Structured Query Language) is a standard language used to interact with relational databases. SQL operators are crucial tools within this language, allowing users to perform various operations on the data stored in databases. This handbook cove...

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A Beginner's Handbook to SQL Operators

Start from the beginning

by saks12sak12

                                        
                                                    '''sql
  SELECT  FROM employees WHERE age > 30 AND department = 'HR';
  '''
- OR: Combines two conditions; either can be true.
  '''sql
  SELECT  FROM employees WHERE age > 30 OR department = 'HR';
  '''
- NOT: Negates a condition.
  '''sql
  SELECT  FROM employees WHERE NOT department = 'HR';
  '''
 4. Bitwise Operators
Bitwise operators perform bit-level operations on integer data.
- AND ('&'): Bitwise AND.
  '''sql
  SELECT 5 & 3;  -- Result: 1
  '''
- OR ('|'): Bitwise OR.
  '''sql
  SELECT 5 | 3;  -- Result: 7
  '''
- XOR ('^'): Bitwise XOR.
  '''sql
  SELECT 5 ^ 3;  -- Result: 6
  '''
- NOT ('~'): Bitwise NOT.
  '''sql
  SELECT ~5;  -- Result: -6 (depends on the SQL implementation)
  '''
 5. Set Operators
Set operators combine results from two or more queries.
- UNION: Combines results of two queries and removes duplicates.
  '''sql
  SELECT name FROM employees
  UNION
  SELECT name FROM managers;
  '''
- UNION ALL: Combines results of two queries, including duplicates.
  '''sql
  SELECT name FROM employees
  UNION ALL
  SELECT name FROM managers;
  '''
- INTERSECT: Returns common records from two queries.
  '''sql
  SELECT name FROM employees
  INTERSECT
  SELECT name FROM managers;
  '''
- EXCEPT (or MINUS): Returns records from the first query that are not in the second query.
  '''sql
  SELECT name FROM employees
  EXCEPT
  SELECT name FROM managers;
  '''
 6. Other Useful Operators
- LIKE: Searches for a specified pattern in a column.
  '''sql
  SELECT  FROM employees WHERE name LIKE 'A%';  -- Names starting with 'A'
  '''
- IN: Checks if a value matches any value in a list.
  '''sql
  SELECT  FROM employees WHERE department IN ('HR', 'Finance');
  '''
- BETWEEN: Selects values within a range.
  '''sql
  SELECT  FROM employees WHERE age BETWEEN 30 AND 40;
  '''
- IS NULL: Checks for null values.
  '''sql
  SELECT  FROM employees WHERE manager_id IS NULL;
  '''
- IS NOT NULL: Checks for non-null values.
  '''sql
  SELECT  FROM employees WHERE manager_id IS NOT NULL;
  '''
 Conclusion
This beginner's handbook covers essential SQL operators that form the foundation of querying and manipulating data within a relational database. Understanding and using these operators effectively will enable you to perform a wide range of database operations, from simple queries to complex data manipulations. Happy querying!