SQL Online Quiz

Q 1 - Consider the following schema −

STUDENTS(student_code, first_name, last_name, email, 
         phone_no, date_of_birth, honours_subject, percentage_of_marks);

Which of the following query would display names of all the students whose email ids are not provided?

A - select first_name, last name from students where email = 0;

B - select first_name, last name from students where email = ‘ ‘;

C - select first_name, last name from students where email is null;

D - select first_name, last name from students where email = ‘null’;

Q 2 - What is returned by SUBSTR(‘TUTORIALS POINT’, 1, 9)?

A - TUTORIAL

B - POINT

C - TUTORIALS

D - UTORIALS

Q 3 - Which of the following is true about SQL joins?

A - The join condition is not separated from other search conditions in a query.

B - The ON clause makes code difficult to understand.

C - The join condition for natural join is basically an equijoin of all columns with same name.

D - None of the above.

Q 4 - Which of the following functions can be used on both numeric as well as non-numeric data?

A - COUNT

B - AVG

C - STDDEV

D - VARIANCE

Q 5 - Which of the following is true about subqueries?

A - Subqueries could be used for Top-N analysis.

B - Subqueries can be of two types – single-row subquery and multiple-row subquery.

C - The outer and inner queries can get data from different tables.

D - All of the above.

Q 6 - Which of the following is not true about inserting news rows to a table?

A - The INSERT INTO statement is used for inserting new rows to a table

B - You cannot insert rows with NULL values to a table.

C - You may insert a new row containing values for each column.

D - All of the above.

Q 7 - Consider the following schema −

LOCATIONS(subject_code, department_name, location_id, city);

Which code snippet will alter the table LOCATIONS and add a column named Address, with datatype VARCHAR2(100)?

A - ALTER TABLE locations ADD (address varchar2(100));

B - ALTER TABLE locations ADD COLUMN(address varchar2(100));

C - MODIFY TABLE locations ADD COLUMN (address varchar2(100));

D - None of the above.

Q 8 - Which of the following code will successfully delete the table LOCATIONS from the database?

A - DROP TABLE locations;

B - DELETE TABLE locations;

C - TRUNCATE TABLE locations;

D - None of the above.

Q 9 - Which of the following is true about database indexes?

A - You can create an index on one or more columns.

B - Indexes always slow down the speed of query process.

C - Indexes are always created automatically.

D - Indexes should ideally be created on small tables.

Q 10 - Which of the following is not a developer’s privilege?

A - CREATE USER

B - CREATE TABLE

C - CREATE VIEW

D - CREATE SEQUENCE