SQL

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create table employee(

empId  int not null unique,

empName varchar(40) not null);

CREATE TABLE DEPARTMENT

(DEPT_ID INT NOT NULL UNIQUE,

 DEPT_NAME VARCHAR(40) NOT NULL);

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insert into employee values(1,'Takshila');

insert into employee values(2,'Vidushi');

insert into employee values(3,'Priyanka');

insert into employee values(4,'Kiran');select

insert into department values(1,'HR');

insert into department values(2,'ADMIN');

insert into department values(3,'CORE ENGINEERING');

insert into department values(4,'QA');

UPDATE  employee SET salary =10000 where empid= 1;

UPDATE employee SET salary =20000 where empid= 2;

UPDATE  employee SET salary =30000 where empid= 3;

UPDATE employee SET salary =40000 where empid= 4;

SELECT TOP 2 column FROM employee[oracle]

select count(*) from employee

4 records

select max(salary) from employee

40000

select salary from employee order by salary desc limit 2 

40000

30000

select salary from employee order by salary fetch first 2 rows only 

o/p

10000

40000

SELECT Salary FROM (select * from employee order by salary desc limit 2)  as A order by salary limit 1 

[SELECT Salary FROM (select * from employee order by salary desc limit 2)  as A order by salary limit 1 ]

[SELECT  MAX(salary) AS salary

  FROM employee

 WHERE salary < (SELECT MAX(salary)

                 FROM employee); ]

Select min(A.salary) from  (Select * from employee  order by salary desc limit 2 ) as A 

-----------------------------------------

select * from employee

____________________________

ALTER TABLE TO ADD COLUMN

Alter table employee add column salary int ;

ALTER TABLE TO ADD CONSTRAINT

ALTER TABLE TO RENAME TABLE

TRUNCATE TABLE Employee; 

ALTER TABLE table_name   RENAME TO new_table_name;  

TRUNCATE TABLE Employee;  

SQL COPY TABLE

SELECT * INTO  FROM  

SQL DELETE TABLE

DELETE FROM table_name [WHERE condition];  

SQL UPDATE

UPDATE students  
SET User_Name = 'beinghuman'  
WHERE Student_Id = '3'