SQL Basic Commands

Create database

Create database statement is used to create a database in SQL

Syntax:

Create database databasename;

Example:

Create Database LP;   
   

Select database

It is used to select the database.

Syntax:

use databasename;

Example:

use LP;

Create table:

Create table statement is used to create a table in SQL
Syntax:

 Create table table name( fieldname1 datatype,fieldname2 datatype...);

Example:

Create table DPK (Employee_ID  INT  Not  NULL,Employee_Name Varchar (20)NOT NULL, Salary decimal(7,2) NOT NULL ,PRIMARY KEY (Employee_ID));    

Note:

salary decimal(7,2)

The first argument is precision,which is the number of total digits.The second argument is scale which is the maximum number of digits to the right of the decimal point. 

Example:

34567.23,23478.45

Insert statement:
Insert statement is used to insert data into table in SQL
Syntax: 

INSERT INTO table_name (column1, column2, column3,...)
VALUES (value1, value2, value3,...)

Example:

INSERT into DPK(Employee_ID, Employee_Name,Salary) values (101, 'Ram Kumar',89555.78 );

 INSERT into DPK(Employee_ID, Employee_Name,Salary) values (102, 'suryosnata',55000.79);

  INSERT into DPK(Employee_ID, Employee_Name,Salary) values (103, 'Dipak',90000.58 );

Select statement:
It is used to retrieve data from table.

Syntax:

SELECT statement is used to select data from one or more tables:

SELECT column_name(s) FROM table_name;

We can use the * character to select ALL columns from a table

Select*from  table name;

Example:

  Select * from DPK;

Update statement

Update statement is used to update existing records in a table
Syntax: 

UPDATE table_name
SET column1=value, column2=value2,...
WHERE some_column=some_value 

Example:

update  DPK set Employee_Name='debasish' where Employee_Name='Ram Kumar';

Delete statement:

delete statement is used to delete records from a table
Syntax: 

delete form table name

Or

DELETE  FROM table_name
WHERE some_column = some_value

Example:

Delete from DPK where Employee_ID=101;

Commands:

// Create Database

 Create Database LP;   
   

 //Select Database

  Use LP;          
               

//Create table DPK

Create table DPK (Employee_ID INT Not NULL,Employee_Name Varchar (20)NOT NULL, Salary decimal(7,2) NOT NULL ,PRIMARY KEY (Employee_ID));    

//Retrieve  Data from DPK

  Select * from DPK;

//Insert Data into DPK

INSERT into DPK(Employee_ID, Employee_Name,Salary) values (101, 'Ram Kumar',89555.78 );

INSERT into DPK(Employee_ID, Employee_Name,Salary) values (102, 'suryosnata',55000.79);

INSERT into DPK(Employee_ID, Employee_Name,Salary) values (103, 'Dipak',90000.58 );

//Retrieve  Data from DPK

Select * from DPK;

//Update data

 update  DPK set Employee_Name='debasish' where Employee_Name='Ram Kumar';

Select * from DPK;

//Delete data

Delete from DPK where Employee_ID=101;

Select * from DPK;