SQL Programming: Retrieving data using SELECT using Operators

 

Access the database from here:

livesql.oracle.com

select * from HR.Employees;

Select First_name, email from HR.Employees where department_id = 60;

Select distinct department_id from HR.Employees;

Select distinct Last_name,  job_id from HR.Employees order by job_id;

Creating temporary column and giving it an alias
Select first_name, Last_name,  job_id, salary, salary*1.2 "Diwali Bonus" from HR.Employees order by job_id;

Select first_name, Last_name, first_name||'.'||last_name||'@mycompany.com' Email_ID from HR.Employees order by job_id;

desc hr.employees

Handling Null values:
select * from HR.Employees where COMMISSION_PCT is NOT NULL;
select * from HR.Employees where COMMISSION_PCT is NULL;

select * from HR.Employees where DEPARTMENT_ID in (80,60);
select * from HR.Employees where DEPARTMENT_ID =80 OR Department_ID = 60;
select * from HR.Employees where DEPARTMENT_ID =80 AND JOB_ID='SA_REP' AND COMMISSION_PCT <=0.2;

select * from HR.Employees where DEPARTMENT_ID =80 AND JOB_ID='SA_REP' AND COMMISSION_PCT <=0.2 Order by First_name
select * from HR.Employees where DEPARTMENT_ID =80 AND JOB_ID='SA_REP' AND COMMISSION_PCT <=0.2 Order by First_name DESC;
select * from HR.Employees where DEPARTMENT_ID =80 AND JOB_ID='SA_REP' AND COMMISSION_PCT <=0.2 Order by 4 DESC;
select * from HR.Employees where DEPARTMENT_ID =80 AND JOB_ID='SA_REP' AND COMMISSION_PCT <=0.2 Order by HIRE_DATE, First_name DESC, 4;

select * from HR.Employees  Order by COMMISSION_PCT NULLS FIRST, First_name;

select * from HR.Employees  Where  Department_ID BETWEEN 40 and 80 Order by Department_ID;

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     OPERATORS
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*,/,+,-

||
NOT
= <= < >= >, IN, LIKE  -  WHERE
AND
OR