Differentiate Unique and Primary Key constraint.

Distinguish Between

Unique Key Constraint	Primary Key Constraint
The constraint ensures that no two rows have the same value in the specified columns.	This constraint declares a field as a Primary Key which helps to uniquely identify a record.
The UNIQUE constraint can be applied only to fields that have also been declared as NOT NULL.	The Primary Key does not allow NULL values and therefore a field declared as Primary Key must have the NOT NULL constraint.

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SQL Commands and Their Functions

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Chapter 12: Structured Query Language (SQL) - Evaluation [Page 230]

Chapter 12 Structured Query Language (SQL)
Evaluation | Q 2. | Page 230

The command to delete a table is ______

Write a query that selects all students whose age is less than 18 in order wise.

Which component of SQL lets inserts values in tables and which lets to create a table?

Write a SQL statement to modify the student table structure by adding a new field.

Write any three DDL commands.

Write a SQL statement using the DISTINCT keyword.

Write the different types of constraints and their functions.

Consider the following employee table. Write SQL commands for the question.

To add a new row.

What are the components of SQL? Write the commands in each.

Construct the following SQL statement in the student table-

SELECT statement using GROUP BY clause.