This set of MySQL Database Multiple Choice Questions & Answers (MCQs) focuses on “MySQL Setup – 1”.
Explanation: The ‘LIKE’ clause filters information that match a given pattern. ‘WHERE’ clause selects information that is specified by a condition. ‘IS’ is used to match the exact condition specified.
2. What column names are displayed when this command is executed?
SHOW COLUMNS FROM tbl_name LIKE '%name';
a) suffixed with ‘name’
b) prefixed with ‘name’
c) suffixed with ‘%name’
d) prefixed with ‘%name’
Explanation: The wildcard ‘%’ is used to indicate that any number of characters can replace it. All column names that end in ‘name’ are displayed. Additional information of columns like type and size are listed.
3. The special database that always exists after setting up MySQL in a computer is __________
Explanation: After installation of MySQL, ‘information_schema’ is the special database that always exists. ‘mysql’ can be seen depending on access rights. It holds the grant tables. ‘sampdb’ and ‘readme_db’ do not exist by default.
CREATE TABLE student ( name CHAR(30), student_id INT, PRIMARY KEY (student_id) ) ENGINE = InnoDB;
a) database name
b) table name
c) reference engine
d) storage engine
Explanation: ‘InnoDB’ is the name of the ‘storage engine’ for the above table. The ‘ENGINE’ clause is used to specify the name of the storage engine that MySQL should use to handle the table being created. MySQL has several storage engines with its own properties.
5. Identify the table name in the following statement.
INSERT INTO student VALUES('Kyle','M',NULL);
Explanation: The ‘INSERT INTO’ clause here inserts a row in the table named ‘student’. The table has three fields. The first field or attribute value in the row/tuple is ‘Kyle’. The second attribute value is ‘M’ and the last attribute is set to NULL.
SELECT abc FROM xyz;
a) row name
b) column name
c) table name
d) database name
Explanation: The SELECT clause is used to retrieve information from some specified tables. It follows a specified format for information retrieval. Here, ‘abc’ can be a column name. It must be present in the table ‘xyz’.
7. Which operator is used to perform integer divisions in MySQL?
Explanation: The operator ‘DIV’ is used to perform integer divisions in MySQL. ‘//’ is used in languages like Python to do the same. The operator ‘/’ performs floating point divisions and ‘\’ is facilitates escape sequences.
8. The NULL value also means ___________
a) value equal to zero
b) unknown value
c) negative values
d) a large value
Explanation: The NULL value in MySQL is a special value. It represents ‘no value’ or an ‘unknown value’. A NULL value can’t be compared like normal known values since it gives undesirable results.
9. What does comparing a known value with NULL result into?
b) a positive value
c) a negative value
Explanation: In MySQL, NULL is not comparable to other known values. It will result in a NULL when compared to any value. The following statement would result in four NULLs: ‘SELECT NULL = 0, NULL < 0, NULL <> 0, NULL > 0’.
10. Which clause is used to sort query elements?
b) GROUP BY
d) ORDER BY
Explanation: An ‘ORDER BY’ clause specifies the sort order. The data is sorted in ascending order by default. To sort in descending order, the keyword DESC is appended to the ‘ORDER BY’ clause. ‘GROUP BY’ is used to group the query results according to a criteria.
Sanfoundry Global Education & Learning Series – MySQL Database.
To practice all areas of MySQL Database, here is complete set of 1000+ Multiple Choice Questions and Answers.