how to compare a string in sql code example

Example 1: sql compare strings

SELECT * FROM table WHERE Column = 'test';			-- can use index
SELECT * FROM table WHERE Column LIKE '%test%';		-- can't use index
SELECT * FROM table WHERE CONTAINS(Column, 'test'); -- faster with full text index

Example 2: how to compare in sql

(Between) operator same as  ">= <="
For example: 
Select * From Employees Where salary Between 4000 AND 6000;

(NOT) operator excluding given
For example:
Select last_name, job_id From Employees
Where "Not" job_id = 'ABC';


(IN) operator in sql like "OR" operator
For example: 
Select * From employees
Where department_id "IN" (60,90); 


(Like) Operator for partial searches using wildcard '%' and '_'
For Example:
Select * From Employees
Where last_name LIKE '_a%';


(Top N results)
Select * From Employees Where ROWNUM <=5;


(NVL) replaces NULL values with same type default
value provided.
For Example = 
Select NVL(commission_percentage, 0)
From Employees;