SQL DML Commands SELECT, INSERT, UPDATE, DELETE SQL Operators DBMS_Lect-9_Hindi
INSERT DML Command
INSERT is another most important data manipulation command in Structured Query Language, which allows users to insert data in database tables.
Syntax of INSERT Command
INSERT INTO TABLE_NAME ( column_Name1 , column_Name2 , column_Name3 , .... column_NameN ) VALUES (value_1, value_2, value_3, .... value_N ) ;
Examples of INSERT Command
Example 1: This example describes how to insert the record in the database table.
Let's take the following student table, which consists of only 2 records of the student.
Stu_Id Stu_Name Stu_Marks Stu_Age
101 Ramesh 92 20
201 Jatin 83 19
Suppose, you want to insert a new record into the student table. For this, you have to write the following DML INSERT command:
INSERT INTO Student (Stu_id, Stu_Name, Stu_Marks, Stu_Age) VALUES (104, Anmol, 89, 19);
UPDATE DML Command
UPDATE is another most important data manipulation command in Structured Query Language, which allows users to update or modify the existing data in database tables.
Syntax of UPDATE Command
UPDATE Table_name SET [column_name1= value_1, ….., column_nameN = value_N] WHERE CONDITION;
Here, 'UPDATE', 'SET', and 'WHERE' are the SQL keywords, and 'Table_name' is the name of the table whose values you want to update.
Examples of the UPDATE command
Example 1: This example describes how to update the value of a single field.
Let's take a Product table consisting of the following records:
Product_Id Product_Name Product_Price Product_Quantity
P101 Chips 20 20
P102 Chocolates 60 40
P103 Maggi 75 5
P201 Biscuits 80 20
P203 Namkeen 40 50
Suppose, you want to update the Product_Price of the product whose Product_Id is P102. To do this, you have to write the following DML UPDATE command:
UPDATE Product SET Product_Price = 80 WHERE Product_Id = 'P102' ;
Example 2: This example describes how to update the value of multiple fields of the database table.
Let's take a Student table consisting of the following records:
Stu_Id Stu_Name Stu_Marks Stu_Age
101 Ramesh 92 20
201 Jatin 83 19
202 Anuj 85 19
203 Monty 95 21
102 Saket 65 21
103 Sumit 78 19
104 Ashish 98 20
Suppose, you want to update Stu_Marks and Stu_Age of that student whose Stu_Id is 103 and 202. To do this, you have to write the following DML Update command:
UPDATE Student SET Stu_Marks = 80, Stu_Age = 21 WHERE Stu_Id = 103 AND Stu_Id = 202;
DELETE DML Command
DELETE is a DML command which allows SQL users to remove single or multiple existing records from the database tables.
This command of Data Manipulation Language does not delete the stored data permanently from the database. We use the WHERE clause with the DELETE command to select specific rows from the table.
Syntax of DELETE Command
DELETE FROM Table_Name WHERE condition;
Examples of DELETE Command
Example 1: This example describes how to delete a single record from the table.
Let's take a Product table consisting of the following records:
Product_Id Product_Name Product_Price Product_Quantity
P101 Chips 20 20
P102 Chocolates 60 40
P103 Maggi 75 5
P201 Biscuits 80 20
P203 Namkeen 40 50
Suppose, you want to delete that product from the Product table whose Product_Id is P203. To do this, you have to write the following DML DELETE command:
DELETE FROM Product WHERE Product_Id = 'P202' ;
Example 2: This example describes how to delete the multiple records or rows from the database table.
Let's take a Student table consisting of the following records:
Stu_Id Stu_Name Stu_Marks Stu_Age
101 Ramesh 92 20
201 Jatin 83 19
202 Anuj 85 19
203 Monty 95 21
102 Saket 65 21
103 Sumit 78 19
104 Ashish 98 20
Suppose, you want to delete the record of those students whose Marks is greater than 70. To do this, you have to write the following DML Update command:
DELETE FROM Student WHERE Stu_Marks 70 ;