PostgreSQL Queries

ERP:

ERP (Enterprise Resource Planning) is an integrated software system that a company uses to manage and automate core daily processes—such as finance, HR, manufacturing, supply chain, procurement, and sales—using a single shared database.

Major ERP Organizations & Providers in India:

1. Ramco Systems
2. Marg ERP
3. Tally Solutions
4. Zoho Corporation
5. SAP India & Oracle India
6. ERPNext / Frappe

CRM:

• CRM stands for Customer Relationship Management.
• It is a software system that helps businesses store customer data, track sales, automate daily tasks, and manage communication across teams in one central place.

Major CRM Providers in India:

1. Salesforce
2. HubSpot
3. Zoho CRM
4. Microsoft Dynamics 365
5. Freshsales (Freshworks)

Creating a table

create table employee(
empid integer, 
name varchar(25), 
designation varchar(25), 
dept varchar(25), 
salary integer);

output:
CREATE TABLE

to see the structure of the table using this command

\d employee;

to see the list of databases using this command

\l cinemas;

to insert values

insert into employee values(123, 'Kavin', 'Software Engineer','DB',25000);
insert into employee values(124, 'Viyan', 'Software Engineer', 'AI',27000);

output:
INSERT 0 1
INSERT 0 1

insert into employee values(101, 'Arul', 'Team Lead',  'Front End', 35000), (101, 'Agaran', 'Team Lead',  'DB', 45000);

output:
INSERT 0 2

to read the name and designation column in table

select name, designation from employee;

to rename a table name

alter table employee rename to employees;

Output:
ALTER TABLE

insert into employees values(111, 'Mugilan', 'Team Lead', 35000), (118, 'Pari', 'SQL Developer', 45000);

output:
INSERT 0 2

to see output without duplicates using distinct keyword

select distinct designation from employees;

using where clause

select * from employees where dept = 'DB';

AND keyword

select * from employees where dept ='DB' and designation = 'Team Lead';

OR keyword

select * from employees where dept ='DB' or designation = 'Team Lead';

as keyword used to assign new name in view

select name as empname, dept as Department from employees;

not keyword(not or <> or !=)

select * from employees where not dept <> 'DB';

(>) operator

select * from employees where salary > 28000;

between keyword

select * from employees where salary between 19000 and 35000;

in keyword

select * from employees where dept in ('DB', 'FE', 'AI');

order by keyword

select * from employees order by salary asc, dept desc;

limit keyword

select * from employees order by salary limit 3;

like keyword

select * from employees where name like 'A%';