MCQs – SQL Basics

Q) To combine the result-set of two or more SELECT statements, SQL clause used is

1. SQL UNION
2. SQL JOIN
3. SQL GROUP BY
4. NONE

Answer: 1

SQL Join statement is used to combine result set from two or more tables.

Q) In a sql subquery , which operator is used to check for existence of record ?

1. SQL NOT NULL
2. SQL AS
3. SQL EXISTS
4. NONE

Answer: 3
The EXISTS operator returns true if the subquery returns one or more records.

Q) Correct SQL query syntax to update a record from a table is

1. UPDATE table_name

SET column1 = value1, column2 = value2, …
WHERE condition;

1. UPDATE table_name
   SET COLUMN column1 = value1, column2 = value2, …
   WHERE condition;
2. UPDATE table_name
   UPDATE column1 = value1, column2 = value2, …
   WHERE condition;
3. UPDATE table_name
   column1 = value1, column2 = value2, …
   WHERE condition;

Answer: 1

Q) Which is called as a virtual table in SQL?

1. INNER JOIN
2. JOIN
3. VIEW
4. NONE

Answer: 3
In SQL, the view is a virtual table based on the result-set of an SQL statement.