Comparison and Logical Condition in SQL

Comparison Condition:-
                    Comparison conditions are used in conditions that compare one expression to another value or expression. These operator are used in WHERE condition.



Comparison Operator:-
                   
1. Equal to (=):-

    SELECT *
    FROM EMPLOYEES
    WHERE EMPLOYEE_ID = 100;
   
2. GREATER THAN (>):-

    SELECT *
    FROM EMPLOYEES
    WHERE SALARY > 4000;
   
3. LESS THAN (<):-

    SELECT *
    FROM EMPLOYEES
    WHERE SALARY < 5000;
   
4. GREATER THAT OR EQUAL TO (>=)   

    SELECT *
    FROM EMPLOYEES
    WHERE SALARY >= 4000;
   
5. LESS THAN OR EQUAL TO (<=):-

    SELECT *
    FROM EMPLOYEES
    WHERE SALARY <= 5000;
   
6. NOT EQUAL TO (<>):-

    SELECT *
    FROM EMPLOYEES
    WHERE DEPARTMENT_ID <> 50;
   
   
Others Comparison Operator:-

1. BETWEEN .. AND ..:- Between two value(include)

    SELECT *
    FROM EMPLOYEES
    WHERE DEPARTMENT_ID BETWEEN (200 AND 300);
   
2. IN:- Match any of the list of values

    SELECT *
    FROM EMPLOYEES
    WHERE EMPLOYEE_ID IN(101, 110, 200, 220, 109);


3. LIKE:- Match a character pattern.

    SELECT *
    FROM EMPLOYEES
    WHERE LAST_NAME LIKE '%A%';
   
4. IS NULL:- Is a null value.

    SELECT *
    FROM EMPLOYEES
    WHERE COMMISSION_PCT IS NULL;
   
   
Logical Condition:-

1. AND:- If both compare condition are TRUE then it return TRUE.

    SELECT *
    FROM EMPLOYEES
    WHERE SALARY < 20000
    AND DEPARTMENT_ID = 20;

2. OR:- If any one compare condition is TRUE then it return TRUE.
   
    SELECT *
    FROM EMPLOYEES
    WHERE SALARY < 20000
    OR DEPARTMENT_ID = 20;
   
3. NOT:- If condition is false then it return TRUE.

    SELECT *
    FROM EMPLOYEES
    WHERE DEPARTMENT_ID NOT IN(10,50);