SQ
SQL can be expanded as Structured Query Language. It is used to create, manipulate and delete data in a database. This language facilitates very easy database interactions. SQL statements are simple and easy to execute.
Query
Query is a statement which is used to manipulate data available in a database, granting users roles and permissions, creating new databases, creating new tables, deleting table values etc.
Creating New Tables
Using a single statement we can able to create a new table. The following query when executed creates a new table.
Syntax
Create table TABLE_NAME (VARIABLES)
Example
Create table employee (name VARCHAR (20), num NUMBER (5))
The above query creates employee table with name and num fields. It has the ability to store number of names with their employee numbers.
Inserting Values to New Table
Insert statement is used to insert a new record into the table. The Insert statement has the following syntax.
Syntax
Insert into TABLE_NAME (VALUES)
Example
Insert into employee ('xxx', 30)
Modifying Values in a Table
We can able to modify the values available in a table by using the update query. The update query has the following syntax.
Syntax
Update TABLE_NAME set VARIABLE = VALUE where CONDITION
Example
Update employee set name='xyz' where num=30
Selecting a Particular Record
A particular record can be fetched from the table. It can be evaluated by using the select query.
Syntax
Select VARIABLES from TABLE_NAME
Example
Select name, num from employee where num=30
The above query when executed checks the database for num=30 if the condition is satisfied then the particular query will be fetched from the table.
Deleting a Record from the Table
A particular record can be deleted from the table using the following query. Using the delete statement we can able to delete a single record or a group of record having a same attribute.
Syntax
Delete from TABLE_NAME where CONDITION
Example
Delete from employee where num=30
This article describes the basic SQL operations such as creating a table, selecting values from the table, inserting a new record, modifying an existing record, deleting a record. All these queries form the basis for the database operations.
