DML Commands: Insert, Delete, Update

Insert

The INSERT INTO statement of SQL is used to insert a new row in a table. There are two ways of using INSERT INTO statement for inserting rows:

1. Only values: First method is to specify only the value of data to be inserted without the column names.

INSERT INTO table_name VALUES (value1, value2, value3,…);

table_name: name of the table.

value1, value2,.. : value of first column, second column,… for the new record

2. Column names and values both: In the second method we will specify both the columns which we want to fill and their corresponding values as shown below:

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

table_name: name of the table.

column1: name of first column, second column …

value1, value2, value3 : value of first column, second column,… for the new record

Delete

The DELETE Statement in SQL is used to delete existing records from a table. We can delete a single record or multiple records depending on the condition we specify in the WHERE clause.

Syntax: Basic

DELETE FROM table_name WHERE some_condition;

table_name: name of the table

some_condition: condition to choose particular record.

Update

The UPDATE statement in SQL is used to update the data of an existing table in database. We can update single columns as well as multiple columns using UPDATE statement as per our requirement.

Basic Syntax

UPDATE table_name SET column1 = value1, column2 = value2,…

WHERE condition;

table_name: name of the table

column1: name of first , second, third column….

value1: new value for first, second, third column….

condition: condition to select the rows for which the values of columns needs to be updated.