MY SQL

In this we have used databases aditya & table named student have roll, name, and marks and address respectively.

SQL COMMANDS (BASICS)

To show databases -- show databases;
To use databases -- use aditya;
To create table -- create table student(roll int, name char(20), marks float, address char(50));
To insert values into table -- insert into student values(1,’Aditya’,70,‘New Delhi’);
To see table -- select * from students;

1) Deletion Commands

· To delete databases -- drop/delete database aditya;

· To delete table -- drop/delete table students;

· To delete under condition -- delete from student where roll>2;

2) Creating tables

· To create table with not null -- create table student(roll int NOT NULL, name char(20), marks float, address char(50));

· To create table with unique constraint -- create table student(roll int UNIQUE, name char(20), marks float, address char(50));

· To create table with primary key -- create table student(roll int primary key, name char(20), marks float, address char(50));

· To create table with default value -- create table student(roll int default=’E1’, name char(20), marks float, address char(50));

· To create with check Constraint -- create table student(roll int check(roll>10), name char(20), marks float, address char(50));

3) Special commands

· To display Name of those who has roll number >10 -- select name from student where roll>10;

· To Display record of student whose roll no. lies b/w 2 to 20 -- select * from student where roll between 2 and 20;

· To Display record of student whose roll no. lies 2 & 20 -- select * from student where(roll=2 and roll=20) ;

· To Display record of student whose Address is not delhi -- select * from student where address <>’delhi’;

· To Display record of student order by roll no. -- select * from student order by roll;

· To Display record of student whose name contain NA -- select * from student where name is like ’%NA%’;

· To Display record of student whose name contain 4 letters -- select * from student where name is like ’____’;

· To update table -- update student set roll=roll+50;

· To do union -- select * from student union select * from student1;

· To add column read -- alter student read char(20);

· Count/frequency of table -- select count(*) from student;

· Eliminate redundant data -- select distinct name from student;

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