SQL : COMMANDS

 

SQL commands :

DESCRIPTION:

SQL commands in PHP are instructions written in SQL and executed through PHP to manage database data.

  1.SHOW COMMAND

DESCRIPTION:

                       The SHOW command is used to display database information.

 Command Line:

                           SHOW Object_Name;

👉 Syntax:

                   SHOW DATABASES;

       EXAMPLE:

                             

     INPUT :  show databases;

     

    OUTPUT: 

                Database

                 college

SUMMARY

   2. USE COMMAND:

                    DESCRIPTION:

                                            Used to select a database to work with.

          

              Command Line:

                                         USE database_name;

👉 Syntax:

                      USE college;

Example:

                   

INPUT:

              USE college;

    OUTPUT:

                  Database changed

Summary:

               USE command is used to select a database for performing operations.

3 .CREATE COMMAND

      DESCRIPTION:

                              Used to create new database or table in SQL.

         

         Command Line:         CREATE object_name;

      👉 Syntax:

                        CREATE DATABASE college;

                           CREATE TABLE students (

                          id INT PRIMARY KEY,

                          name VARCHAR(100),

                         email VARCHAR(100)

                          );

 Example:

                 

INPUT:

      CREATE TABLE  Students;

    OUTPUT:

                      Database created

 Summary:

CREATE command is used to create database and tables.

4. DESCRIBE COMMAND :

DESCRIPTION:

Used to display the structure of a table (columns, data types, keys).

Command Line:

DESCRIBE table_name;

👉 Syntax:

          DESCRIBE students;

          Example:

         

  INPUT

DESCRIBE students;

  OUTPUT:

Field     Type           Null  
id        int            NO   
name      varchar(100)   YES
email     varchar(100)   YES

     

 Summary:

               DESCRIBE command is used to show table structure (columns and data types).                                                   

5.   SELECT COMMAND:

  DESCRIPTION:

Used to retrieve (fetch) data from a table in a database.

---

 Command Line:

SELECT column_name FROM table_name;

 👉 Syntax:

SELECT * FROM students;

        Example:

  INPUT

        SELECT name, email FROM students;

  OUTPUT:

             name    email

             Raj     raj@gmail.com

 Summary:

                  SELECT command is used to fetch data from a database table.

6. INSERT COMMAND:

              

DESCRIPTION:

                               Used to add data into a table.

 

 Command Line:

            INSERT INTO table_name VALUES (...);

 👉 Syntax:

              INSERT INTO students (name, email) VALUES ('Rajan', 'rajan@gmail.com');

 Example:

  INPUT

       INSERT INTO students (name, email) VALUES ('Rajan', 'rajan@gmail.com');

  OUTPUT:

         Record inserted successfully


 Summary:
                  INSERT command is used to insert new data into a table.
7.UPDATE COMMAND:

DESCRIPTION:
                 Used to modify existing data in a table.



 Command Line:
                    UPDATE table_name SET column_name = value;
👉 Syntax:
               UPDATE students 
               SET email = 'new@gmail.com' 
               WHERE id = 1;



  Example:
          

                                               

 
INPUT:
             UPDATE students 
             SET name = 'Arun' 
             WHERE id = 2;

 OUTPUT:
           Record updated successfully
Summary:
            UPDATE command is used to change existing records in a table.


8. DELETE COMMAND:
                
             DESCRIPTION:
                                      Used to remove (delete) data from a table.

        Command Line:
                                            DELETE FROM table_name;
       👉 Syntax:
                        DELETE FROM students WHERE id = 1;

         Example:

                  
 
           



  INPUT:
             DELETE FROM students WHERE name = 'Rajan';
OUTPUT:
               Record deleted successfully

Summary:
            DELETE command is used to remove records from a table