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In an SQL query, which of the following symbols is used by ANSI SQL to represent all the columns in a single table?
* (asterisk)
In an SQL query, which built-in function is used to compute the average value of numeric columns?
AVG
In an SQL query, which SQL keyword must be used to remove duplicate rows from the result table?
DISTINCT
When making an SQL query, we are using SQL as a(n) ________.
DML
In an SQL query, which SQL keyword is used to determine if a column value is equal to any one of a set of values?
IN
Suppose your company stores EMPLOYEE and CUSTOMER data in separate tables. If you want to find all employees who are also customers, which SQL keyword would you most likely use?
INTERSECT
In an SQL query, which built-in function is used to obtain the largest value of numeric columns?
MAX
In an SQL query, which built-in function is used to obtain the smallest value of numeric columns?
MIN
Explain why it is important to learn SQL.
Most modern DBMS products support SQL as a standardized data language. These products usually provide graphical tools to perform the tasks associated with SQL, but there are some tasks that cannot be performed using these graphical tools. SQL is text-oriented, and SQL code must be written in order to embed SQL commands within program applications.
In an SQL query, which SQL keyword is used to sort the result table by the values in one or more columns?
ORDER BY
Regarding the interchangeability of subqueries and joins, ________.
a join can sometimes be used as an alternative to a subquery, and a subquery can sometimes be used as an alternative to a join
The SQL built-in function ADDUP totals values in numeric columns.
False
The SQL built-in function MOST obtains the largest value in a numeric column.
False
The SQL keyword WHERE is used to specify the table(s) that contain(s) the data to be retrieved.
False
The SQL wildcard character "#" indicates a single, unspecified character in a specific location in an SQL query.
False
The SQL wildcard character "%" represents a series of one or more unspecified characters.
False
The WHERE clause contains the condition that specifies which columns are to be selected.
False
The built-in function SUM can be used with any column.
False
The columns to be obtained by an SQL command are listed after the FROM keyword.
False
To exclude one or more values using a condition, the SQL OUT keyword must be used.
False
To have SQL automatically eliminate duplicate rows from a result, use the keyword DISTINCT with the FROM keyword.
False
To obtain all columns, use an asterisk (*) wildcard character instead of listing all the column names.
False
Two or more tables are joined by giving the table names in the WHERE clause and specifying the equality of the respective column names as a condition in the GROUP BY clause.
False
In an SQL query, which SQL keyword is used with built-in functions to group together rows that have the same value in a specified column or columns?
GROUP BY
The SQL keyword SELECT is used to specify the columns to be listed in the query results.
True
The clause SELECT COUNT (*) results in a table with a single row and a single column.
True
The condition in WHERE clauses can refer to a set of values by using the IN operator.
True
The names of tables to be joined in an SQL query are listed in the FROM clause.
True
The result of an SQL SELECT operation can contain duplicate rows.
True
The rows of the result table can be sorted by the values in one or more columns.
True
To refer to a set of values in a condition, the values are placed inside parentheses ( ) and separated by commas.
True
To refer to a set of values needed for a condition, use the SQL IN operator.
True
To remove duplicate rows from the result of a query, specify the SQL DISTINCT keyword.
True
To sort the rows of the result table, the ORDER BY clause is specified.
True
When people use the term join they normally mean an equijoin.
True
When two conditions must both be true for the rows to be selected, the conditions are separated by the SQL AND keyword.
True
Suppose tables EMPLOYEE and CUSTOMER both store address information, and you want to send a letter to all employees and customers of your company to make a major announcement. Which SQL keyword would you most likely use here
UNION
An ad-hoc query is ________.
a question that can be answered from the database using SQL
When one SQL query is embedded in another SQL query, the top level SQL query can still contain an SQL ________ clause.
GROUP BY
In an SQL query, which SQL keyword is used with GROUP BY to select groups meeting specified criteria?
HAVING
In an SQL query, which of the following symbols is used by Microsoft Access to represent a single unspecified character?
? (question mark)
In an SQL query, which SQL keyword is used to link two conditions that both must be true for the rows to be selected?
AND
In an SQL query, the built-in functions SUM and AVG work with columns containing data of which of the following data types?
Both Integer and Numeric are correct
In an SQL query of two tables, which SQL keyword indicates that we want data from all the rows of one table to be included in the result, even if the row does not correspond to any data in the other table?
Both LEFT JOIN and RIGHT JOIN
In an SQL query, which built-in function is used to compute the number of rows in a table?
COUNT
Given a table with the structure: EMPLOYEE ( EmpNo, Name, Salary, HireDate), which of the following would find all employees whose name begins with the letter "S" using standard SQL?
ELECT * FROM EMPLOYEE WHERE Name LIKE 'S%';
Suppose your company stores EMPLOYEE and CUSTOMER data in separate tables. If you want to find all customers who are not also employees, which SQL keyword would you most likely use?
EXCEPT
In an SQL query, which SQL keyword is used to specify the names of tables to be joined?
FROM
In an SQL query, which SQL keyword is used to specify the table(s) to be used?
FROM
A WHERE clause can contain only one condition.
False
An ad-hoc SQL query is typically written within an application program.
False
Arithmetic in SQL statements is limited to the operations provided by the built-in functions.
False
In addition to being a data sublanguage, SQL is also a programming language, like Java or C#.
False
Only two tables can be queried by using a subquery.
False
SQL can only query a single table.
False
SQL is only a data manipulation language (DML).
False
SQL stands for Standard Query Language.
False
SQL statements end with a colon.
False
SQL, although very popular, has never become a national standard.
False
Sorting is specified by the use of the SORT BY phrase.
False
The Microsoft Access wildcard character "_" (underscore) indicates a single, unspecified character in a specific location in a Microsoft Access SQL query.
False
In an SQL query, which SQL keyword actually begins the query?
SELECT
In an SQL query, which SQL keyword is used to implement a subquery?
SELECT
Given a table with the structure: EMPLOYEE ( EmpNo, Name, Salary, HireDate), which of the following would find all employees whose name begins with the letter "S" using Microsoft Access?
SELECT * FROM EMPLOYEE WHERE Name LIKE 'S*';
Based on the tables below, which of the following ANSI SQL commands would return the average customer balance grouped by SalesRepNo? GENERAL SALES DATABASE: SALESREP SalesRepNo RepName HireDate 654 Jones 01/02/2005 734 Smith 02/03/2007 345 Chen 01/25/2004 434 Johnson 11/23/2004 CUSTOMER CustNo CustName Balance SalesRepNo 9870 Winston 500 345 8590 Gonzales 350 434 7840 Harris 800 654 4870 Miles 100 345
SELECT AVG (Balance) FROM CUSTOMER GROUP BY SalesRepNo;
Given a table with the structure: EMPLOYEE ( EmpNo, Name, Salary, HireDate), which of the following is not a valid ANSI SQL command?
SELECT HireDate, COUNT(*) FROM EMPLOYEE WHERE Salary < 30000;
Given the table CUSTOMER(CustID, Name, PhoneNumber, AccountBalance), write the standard SQL query to retrieve the Name and PhoneNumber of customers whose name begins with 'S'
SELECT Name, PhoneNumber FROM CUSTOMER WHERE Name LIKE 'S%';
Based on the tables below, which of the following commands in ANSI SQL would return only the name of the sales representative and the name of the customer for each customer that has a balance greater than 400? GENERAL SALES DATABASE: SALESREP SalesRepNo RepName HireDate 654 Jones 01/02/2005 734 Smith 02/03/2007 345 Chen 01/25/2004 434 Johnson 11/23/2004 CUSTOMER CustNo CustName Balance SalesRepNo 9870 Winston 500 345 8590 Gonzales 350 434 7840 Harris 800 654 4870 Miles 100 345
SELECT RepName, CustName FROM SALESREP, CUSTOMER WHERE SALESREP.SalesRepNo = CUSTOMER.SalesRepNo AND Balance > 400;
In an SQL query, which of the following symbols is used by ANSI SQL to represent a single unspecified character?
_ (underscore)
What are SQL Built-in Functions?
SQL Built-in Functions are functions that manipulate the results of an SQL SELECT statement. The built-in functions for standard SQL are COUNT, SUM, AVG, MAX, and MIN. The COUNT function counts the number of rows in the result. The SUM function totals the values in a number-oriented field. The AVG function calculates the mean of the values in a number-oriented field. The MAX function determines the highest value, and the MIN function determines the lowest value, in a number-oriented field or any other field whose values can be compared using "<".
In an SQL query, which built-in function is used to total numeric columns?
SUM
What is SQL?
Structured Query Language (SQL) is used to create and use databases, tables, and relationships. SQL is divided into two categories: SQL statements for database definition and SQL statements for database processing (querying and updating). The database definition commands are referred to as a data definition language (DDL), and the database query and update commands are referred to as a data manipulation language (DML). SQL was developed by IBM, and is endorsed as a national standard by the American National Standards Institute (ANSI). Although a newer standard, SQL3, exists, the most widely implemented version of SQL is the ANSI SQL-92 standard. SQL is not a full-featured programming language, but rather it is considered to be a data sublanguage.
Briefly describe subqueries and joins. Explain when each is not an acceptable alternative for the other.
Subqueries and joins are both methods for retrieving data from multiple tables. Subqueries involve nesting one SELECT statement within another. The nested SELECT is used as part of a condition in the WHERE clause of the first SELECT statement. The nested SELECT statement can return a set of records from one table, which are then used in a logical operator within the parent SELECT query. A join combines records from each table into concatenated records containing the fields of both tables. The records are concatenated based on matching values in similar columns in the two tables. Subqueries cannot be used in situations where the results to be displayed include attributes from more than one table. Joins cannot be used as an alternative to a correlated subquery.
Distinguish between the HAVING clause and the WHERE clause.
The HAVING clause and the WHERE clause differ in that the WHERE clause is used to identify rows that satisfy a stated condition. The HAVING clause is used to identify groups, which have been created by the GROUP BY clause, that satisfy a stated condition. In cases when the WHERE clause and the HAVING clause are both allowed to appear in the same SELECT statement, the WHERE clause is implemented to execute before the HAVING clause.
Assuming the "Quantity" column of an ORDER table contains integer data, what does COUNT(Quantity) compute?
The number of non-null values in the Quantity column
A SELECT statement used in a WHERE clause is called a subquery.
True
A WHERE clause can contain another SELECT statement enclosed in parentheses.
True
A nested SELECT statement (one that appears within the WHERE clause of another SQL statement) is called a subquery and must be enclosed in parentheses.
True
An alternative to combining tables by a subquery is to use a join.
True
An asterisk (*) following the SELECT verb means that all columns are to be displayed.
True
Business Intelligence (BI) systems typically store their data in data warehouses.
True
Columns can be sorted in descending sequence by using the SQL DESC keyword.
True
SQL commands can be embedded in application programs.
True
SQL includes a data definition language, a data manipulation language, and SQL/Persistent stored modules.
True
SQL is not a complete programming language. Rather it is a data sublanguage.
True
SQL was developed by IBM in the late 1970s.
True
The American National Standards Institute (ANSI) maintains the standards for SQL.
True
The SQL WHERE clause contains the condition that specifies which rows are to be selected.
True
The SQL built-in function AVG computes the average of values in numeric columns.
True
The SQL built-in function COUNT computes the number of rows in a query.
True
The SQL built-in function MIN obtains the smallest value in a numeric column.
True
The SQL keyword FROM is used to specify the table to be used.
True
The SQL keyword GROUP BY instructs the DBMS to group together those rows that have the same value in a column.
True
The SQL keyword LIKE is used in SQL expressions to select partial string values.
True
In an SQL query, which SQL keyword is used to specify the column names to be used in a join?
WHERE
In an SQL query, which SQL keyword is used to state the condition that specifies which rows are to be selected?
WHERE
When one SQL query is embedded in another SQL query to simulate a join, the second SQL query is embedded in the ________ of the first query.
WHERE
A database extracted from the operational database for BI purposes typically ________.
contains just part of the operational database
SQL is a ________.
data sublanguage
When one SQL query is embedded in another SQL query, this is referred to as a
subquery