SNHU DAD 220 EXAM MANUAL 2025/2026 QUESTIONS
WITH ANSWERS GRADED A+
✔✔What does the date and time function HOUR(t) MINUTE(t) SECOND(t) do? -
✔✔Returns the hour, minute, or second from time t
ex. SELECT HOUR('22:11:45');
returns 22
SELECT MINUTE('22:11:45');
returns 11
SELECT SECOND('22:11:45');
returns 45
✔✔What does the date and time function DATEDIFF(expr1, expr2) TIMEDIFF(expr1,
expr2) do? - ✔✔Returns expr1 - expr2 in number of days or timevalues, given expr1
and expr2 are date, time, or datetime values
ex. SELECT DATEDIFF('2013-03-10', '2013-03-04');
returns 6
SELECT TIMEDIFF('10:00:00', '09:45:30');
returns 00:14:30
✔✔data query language (DQL) - ✔✔extracts data from and about the database
✔✔The SHOW statement - ✔✔shows information about databases, tables, columns,
and server status information
Common examples
SHOW DATABASES lists databases available in the database system.
SHOW TABLES lists tables available in the currently selected database.
SHOW COLUMNS lists columns available in a specific table named by a FROM clause.
SHOW CREATE TABLE shows the CREATE TABLE statement for a given table.
✔✔The SELECT statement - ✔✔retrieves data from a table
✔✔Result set - ✔✔data returned from the SELECT statement, stored in a result table
✔✔The WHERE clause - ✔✔combined with the SELECT statement to filter the result
set. The WHERE clause must come after the FROM clause.
✔✔Condition - ✔✔expression that evaluates to TRUE, FALSE, or NULL. Only a
condition that is TRUE selects the row. Uses a comparison operator
✔✔When will a comparison operator evaluate to NULL? - ✔✔When one or both
operands are NULL. Ex: NULL > 1000 is NULL.
, ✔✔Logical operators - ✔✔AND, OR, AND NOT
✔✔What specifies which logical operators are evaluated first? - ✔✔Parenthesis, if none
AND is evaluated first
✔✔How do logical operators evaluate to NULL? - ✔✔TRUE AND NULL is NULL, but
FALSE AND NULL is FALSE.
✔✔What does the arithmetic operator % do? - ✔✔Returns the integer remainder of a
division between operands
ex. 5 % 2 = 1
✔✔What are arithmetic operators - ✔✔Operators that perform calculations on two
operands. Can be used in the SELECT and WHERE clause
✔✔When is the LIKE operator used? - ✔✔used in conjunction with the WHERE clause
matches text against a pattern using the two wildcard characters % and _
% matches any number of characters. Ex: LIKE 'L%t' matches "Lt", "Lot", "Lift", and "Lol
cat".
_ matches exactly one character. Ex: LIKE 'L_t' matches "Lot" and "Lit" but not "Lt" and
"Loot"
✔✔ In Jeopardy-style online quiz you are playing the "answers" to the bonus question:
1. All non-key columns must depend on the whole primary key 2. A table with a simple
primary key is automatically in this form 3 This form does not eliminate all redundancies
- ✔✔Second normal form
✔✔Denormalization intentionally introduces redundancy by merging tables, and
therefore improves query performance. Which types of normal form tables does it result
in? Select all that apply - ✔✔First or Second form tables.
✔✔When a table is in third normal form, which of these is true? Select one. - ✔✔All
non-key columns depend on the whole primary key and on no other columns.
✔✔You are analyzing data for a new sports stats website and have access to their
databases related to the Major League Baseball games. A coworker has created the
table Attendance, which estimates the average attendance at home games next season
for franchises in each division of the National League and the American League. -
✔✔SELECT League, Division, MAX(Average) FROM Attendance GROUP by League,
Division ORDER by League, Division
WITH ANSWERS GRADED A+
✔✔What does the date and time function HOUR(t) MINUTE(t) SECOND(t) do? -
✔✔Returns the hour, minute, or second from time t
ex. SELECT HOUR('22:11:45');
returns 22
SELECT MINUTE('22:11:45');
returns 11
SELECT SECOND('22:11:45');
returns 45
✔✔What does the date and time function DATEDIFF(expr1, expr2) TIMEDIFF(expr1,
expr2) do? - ✔✔Returns expr1 - expr2 in number of days or timevalues, given expr1
and expr2 are date, time, or datetime values
ex. SELECT DATEDIFF('2013-03-10', '2013-03-04');
returns 6
SELECT TIMEDIFF('10:00:00', '09:45:30');
returns 00:14:30
✔✔data query language (DQL) - ✔✔extracts data from and about the database
✔✔The SHOW statement - ✔✔shows information about databases, tables, columns,
and server status information
Common examples
SHOW DATABASES lists databases available in the database system.
SHOW TABLES lists tables available in the currently selected database.
SHOW COLUMNS lists columns available in a specific table named by a FROM clause.
SHOW CREATE TABLE shows the CREATE TABLE statement for a given table.
✔✔The SELECT statement - ✔✔retrieves data from a table
✔✔Result set - ✔✔data returned from the SELECT statement, stored in a result table
✔✔The WHERE clause - ✔✔combined with the SELECT statement to filter the result
set. The WHERE clause must come after the FROM clause.
✔✔Condition - ✔✔expression that evaluates to TRUE, FALSE, or NULL. Only a
condition that is TRUE selects the row. Uses a comparison operator
✔✔When will a comparison operator evaluate to NULL? - ✔✔When one or both
operands are NULL. Ex: NULL > 1000 is NULL.
, ✔✔Logical operators - ✔✔AND, OR, AND NOT
✔✔What specifies which logical operators are evaluated first? - ✔✔Parenthesis, if none
AND is evaluated first
✔✔How do logical operators evaluate to NULL? - ✔✔TRUE AND NULL is NULL, but
FALSE AND NULL is FALSE.
✔✔What does the arithmetic operator % do? - ✔✔Returns the integer remainder of a
division between operands
ex. 5 % 2 = 1
✔✔What are arithmetic operators - ✔✔Operators that perform calculations on two
operands. Can be used in the SELECT and WHERE clause
✔✔When is the LIKE operator used? - ✔✔used in conjunction with the WHERE clause
matches text against a pattern using the two wildcard characters % and _
% matches any number of characters. Ex: LIKE 'L%t' matches "Lt", "Lot", "Lift", and "Lol
cat".
_ matches exactly one character. Ex: LIKE 'L_t' matches "Lot" and "Lit" but not "Lt" and
"Loot"
✔✔ In Jeopardy-style online quiz you are playing the "answers" to the bonus question:
1. All non-key columns must depend on the whole primary key 2. A table with a simple
primary key is automatically in this form 3 This form does not eliminate all redundancies
- ✔✔Second normal form
✔✔Denormalization intentionally introduces redundancy by merging tables, and
therefore improves query performance. Which types of normal form tables does it result
in? Select all that apply - ✔✔First or Second form tables.
✔✔When a table is in third normal form, which of these is true? Select one. - ✔✔All
non-key columns depend on the whole primary key and on no other columns.
✔✔You are analyzing data for a new sports stats website and have access to their
databases related to the Major League Baseball games. A coworker has created the
table Attendance, which estimates the average attendance at home games next season
for franchises in each division of the National League and the American League. -
✔✔SELECT League, Division, MAX(Average) FROM Attendance GROUP by League,
Division ORDER by League, Division
