PostgreSQL-2

PostgreSQL

In database create table called employee.
create table employee(empid integer, name varchar(25), designation varchar(25),dept varchar(25), salary integer);

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

Add more rows in single insert statement:
insert into employee values(101, 'Arul', 'Team Lead', 'Front End', 35000),
(101, 'Agaran', 'Team Lead', 'DB', 45000);

Change Table Name:
alter table employee rename to employees;

Select:
Using distinct to get unique values
select distinct designation from employees;

where clause:
select * from employees where dept = 'DB';

where, and
select * from employees where dept =’DEV’ and designation = ‘Manager’;

where, or:
select * from employees where dept = ‘’ or designation = ‘’;

as:
select dept as department from employees;
to show the name as we want

Not Equals to:

select * from employees where dept <> ‘DB’;
select * from employees where dept != ‘DB’;
select * from employees where not dept = ‘DB’;

> greater than:
select * from employees where salary > 28000;

between:
select * from employees where salary between 19000 and 35000;

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

and
select * from employees where name ='Kavin' and dept ='DB';

or
select * from employees where name ='Kavin' or dept ='DB';

order by
select * from employees order by dept;(ascending order)
select * from employees order by dept desc;

limit
select * from employees order by salary limit 3;
give first 3 values
select * from employees order by salary desc limit 3;
give lasr 3 values

LIKE Operator
select * from employees where name like ‘A%’;
select * from employees where name like ‘%A%’;