About This Book
by SAS Institute
SAS® Certification Prep Guide: Advanced Programming for SAS®9 Second Edition
- Copyright
- About This Book
- 1. SQL Processing With SAS
- 1. Performing Queries Using PROC SQL
- 2. Performing Advanced Queries Using PROC SQL
- Overview
- Viewing SELECT Statement Syntax
- Displaying All Columns
- Limiting the Number of Rows Displayed
- Eliminating Duplicate Rows from Output
- Subsetting Rows by Using Conditional Operators
- Using Operators in PROC SQL
- Using the BETWEEN-AND Operator to Select within a Range of Values
- Using the CONTAINS or Question Mark (?) Operator to Select a String
- Example
- Using the IN Operator to Select Values from a List
- Using the IS MISSING or IS NULL Operator to Select Missing Values
- Example
- Using the LIKE Operator to Select a Pattern
- Specifying a Pattern
- Example
- Using the Sounds-Like (=*) Operator to Select a Spelling Variation
- Subsetting Rows by Using Calculated Values
- Enhancing Query Output
- Summarizing and Grouping Data
- Number of Arguments and Summary Function Processing
- Groups and Summary Function Processing
- SELECT Clause Columns and Summary Function Processing
- Using a Summary Function with a Single Argument (Column)
- Using a Summary Function with Multiple Arguments (Columns)
- Using a Summary Function without a GROUP BY Clause
- Using a Summary Function with Columns Outside of the Function
- Using a Summary Function with a GROUP BY Clause
- Counting Values by Using the COUNT Summary Function
- Counting All Rows
- Counting All Non-Missing Values in a Column
- Counting All Unique Values in a Column
- Selecting Groups by Using the HAVING Clause
- Understanding Data Remerging
- Example
- Subsetting Data by Using Subqueries
- Subsetting Data by Using Noncorrelated Subqueries
- Subsetting Data by Using Correlated Subqueries
- Validating Query Syntax
- Additional Features
- Summary
- Text Summary
- Viewing SELECT Statement Syntax
- Displaying All Columns
- Limiting the Number of Rows Displayed
- Eliminating Duplicate Rows from Output
- Subsetting Rows by Using Conditional Operators
- Subsetting Rows by Using Calculated Values
- Enhancing Query Output
- Summarizing and Grouping Data
- Subsetting Data by Using Subqueries
- Subsetting Data by Using Noncorrelated Subqueries
- Subsetting Data by Using Correlated Subqueries
- Validating Query Syntax
- Additional Features
- Syntax
- Sample Programs
- Points to Remember
- Text Summary
- Quiz
- 3. Combining Tables Horizontally Using PROC SQL
- Overview
- Understanding Joins
- Generating a Cartesian Product
- Using Inner Joins
- Introducing Inner Join Syntax
- Example
- Understanding How Joins Are Processed
- Eliminating Duplicate Columns
- Renaming a Column by Using a Column Alias
- Joining Tables That Have Rows with Matching Values
- Specifying a Table Alias
- Example: Complex PROC SQL Inner Join
- Example: PROC SQL Inner Join with Summary Functions
- Using Outer Joins
- Creating an Inner Join with Outer Join-Style Syntax
- Comparing SQL Joins and DATA Step Match-Merges
- Using In-Line Views
- Joining Multiple Tables and Views
- Summary
- Quiz
- 4. Combining Tables Vertically Using PROC SQL
- 5. Creating and Managing Tables Using PROC SQL
- Overview
- Understanding Methods of Creating Tables
- Creating an Empty Table by Defining Columns
- Displaying the Structure of a Table
- Creating an Empty Table That Is Like Another Table
- Creating a Table from a Query Result
- Inserting Rows of Data into a Table
- Creating a Table That Has Integrity Constraints
- Handling Errors in Row Insertions
- Displaying Integrity Constraints for a Table
- Updating Values in Existing Table Rows
- Updating Rows by Using the Same Expression
- Example
- Updating Rows by Using Different Expressions
- Example
- How PROC SQL Updates Rows Based on a CASE Expression
- How the Case Operand Works
- Updating Rows by Using the CASE Expression without a Case Operand
- Example
- Updating Rows by Using the CASE Expression with a Case Operand
- Example
- Using the CASE Expression in the SELECT Statement
- Example
- Deleting Rows in a Table
- Altering Columns in a Table
- Dropping Tables
- Summary
- Text Summary
- Understanding Methods of Creating Tables
- Creating an Empty Table by Defining Columns
- Displaying the Structure of a Table
- Creating an Empty Table That Is Like Another Table
- Creating a Table from a Query Result
- Inserting Rows of Data into a Table
- Creating a Table That Has Integrity Constraints
- Handling Errors in Row Insertions
- Displaying Integrity Constraints for a Table
- Updating Values in Existing Table Rows
- Deleting Rows in a Table
- Altering Columns in a Table
- Dropping Tables
- Syntax
- Sample Programs
- Creating an Empty Table by Defining Columns
- Creating an Empty Table That Is Like Another Table
- Creating a Table from a Query Result
- Displaying the Structure of a Table
- Inserting Rows into a Table by Specifying Column Names and Values
- Inserting Rows into a Table by Specifying Lists of Values
- Inserting Rows into a Table from a Query Result
- Creating a Table That Has Integrity Constraints
- Displaying Integrity Constraints for a Table
- Updating Rows in a Table Based on an Expression
- Updating Rows in a Table by Using a CASE Expression
- Updating Rows in a Table by Using a CASE Expression (Alternate Syntax)
- Deleting Rows in a Table
- Adding, Modifying, and Dropping Columns in a Table
- Dropping a Table
- Points to Remember
- Text Summary
- Quiz
- 6. Creating and Managing Indexes Using PROC SQL
- Overview
- Understanding Indexes
- Deciding Whether to Create an Index
- Creating an Index
- Displaying Index Specifications
- Managing Index Usage
- Understanding How SAS Decides Whether to Use an Index
- Determining Whether SAS Is Using an Index
- Example: Query That Uses an Index
- Example: Query That Does Not Use an Index
- Controlling Index Usage
- Using IDXWHERE= to Direct SAS to Use or Not to Use an Index
- Example
- Using IDXNAME= to Direct SAS to Use a Specified Index
- Example
- Dropping Indexes
- Summary
- Quiz
- 7. Creating and Managing Views Using PROC SQL
- 8. Managing Processing Using PROC SQL
- 2. SAS Macro Language
- 9. Introducing Macro Variables
- Overview
- Basic Concepts
- Using Automatic Macro Variables
- Using User-Defined Macro Variables
- Processing Macro Variables
- Displaying Macro Variable Values in the SAS Log
- Using Macro Functions to Mask Special Characters
- Using Macro Functions to Manipulate Character Strings
- Using SAS Functions with Macro Variables
- Combining Macro Variable References with Text
- Summary
- Text Summary
- Basic Concepts
- Using Automatic Macro Variables
- Using User-Defined Macro Variables
- Processing Macro Variables
- Displaying Macro Variable Values in the SAS Log
- Using Macro Functions to Mask Special Characters
- Using Macro Functions to Manipulate Character Strings
- Using SAS Functions with Macro Variables
- Combining Macro Variable References with Text
- Syntax
- Sample Programs
- Points to Remember
- Text Summary
- Quiz
- 10. Processing Macro Variables at Execution Time
- Overview
- Creating a Macro Variable During DATA Step Execution
- Creating Multiple Macro Variables During DATA Step Execution
- Referencing Macro Variables Indirectly
- Obtaining Macro Variable Values During DATA Step Execution
- Creating Macro Variables During PROC SQL Step Execution
- Working with PROC SQL Views
- Using Macro Variables in SCL Programs
- Summary
- Text Summary
- Creating a Macro Variable During DATA Step Execution
- Creating Multiple Macro Variables During DATA Step Execution
- Referencing Macro Variables Indirectly
- Obtaining Macro Variable Values During DATA Step Execution
- Creating Macro Variables During PROC SQL Step Execution
- Working with PROC SQL Views
- Using Macro Variables in SCL Programs
- Syntax
- Sample Programs
- Points to Remember
- Text Summary
- Quiz
- 11. Creating and Using Macro Programs
- 12. Storing Macro Programs
- 9. Introducing Macro Variables
- 3. Advanced SAS Programming Techniques
- 13. Creating Samples and Indexes
- Overview
- Creating a Systematic Sample from a Known Number of Observations
- Creating a Systematic Sample from an Unknown Number of Observations
- Creating a Random Sample with Replacement
- Creating a Random Sample without Replacement
- Using Indexes
- Creating Indexes in the DATA Step
- Managing Indexes with PROC DATASETS
- Managing Indexes with PROC SQL
- Documenting and Maintaining Indexes
- Summary
- Text Summary
- Creating a Systematic Sample from a Known Number of Observations
- Creating a Systematic Sample from an Unknown Number of Observations
- Creating a Random Sample with Replacement
- Creating a Random Sample without Replacement
- Using Indexes
- Creating Indexes in the DATA Step
- Managing Indexes with PROC DATASETS and PROC SQL
- Documenting and Maintaining Indexes
- Syntax
- Sample Programs
- Creating a Systematic Sample from a Known Number of Observations
- Creating a Systematic Sample from an Unknown Number of Observations
- Creating a Random Sample with Replacement
- Creating a Random Sample without Replacement
- Creating an Index in the DATA Step
- Managing Indexes with PROC DATASETS
- Managing Indexes with PROC SQL
- Points to Remember
- Text Summary
- Quiz
- 14. Combining Data Vertically
- 15. Combining Data Horizontally
- Overview
- Reviewing Terminology
- Working with Lookup Values Outside of SAS Data Sets
- Combining Data with the DATA Step Match-Merge
- Using PROC SQL to Join Data
- Comparing DATA Step Match-Merges and PROC SQL Joins
- Combining Summary Data and Detail Data
- Using an Index to Combine Data
- Using a Transactional Data Set
- Summary
- Text Summary
- Reviewing Terminology
- Working with Lookup Values Outside of SAS Data Sets
- Combining Data with the DATA Step Match-Merge
- Using PROC SQL to Join Data
- Comparing DATA Step Match-Merges and PROC SQL Joins
- Combining Summary Data and Detail Data
- Using an Index to Combine Data
- Using a Transactional Data Set
- Syntax
- Sample Programs
- Combining Data with the IF-THEN/ELSE Statement
- Combining Data with the ARRAY Statement
- Combining Data with the FORMAT Procedure
- Performing a DATA Step Match-Merge
- Performing a PROC SQL Join
- Working with a Many-to-Many Match
- Combining Summary Data and Detail Data
- Using an Index to Combine Data
- Using a Transactional Data Set
- Points to Remember
- Text Summary
- Quiz
- 16. Using Lookup Tables to Match Data
- Overview
- Using Multidimensional Arrays
- Using Stored Array Values
- Using PROC TRANSPOSE
- Merging the Transposed Data Set
- Using Hash Objects as Lookup Tables
- The Structure of a Hash Object
- Example
- Data Step Component Objects
- Declaring the Hash Object
- Instantiating the Hash Object
- Declaring and Instantiating the Hash Object in a Single Step
- Defining Keys and Data
- Using the Call Missing Routine
- Loading Key and Data Values
- Retrieving Matching Data
- Hash Object Processing
- Creating a Hash Object From a SAS Data Set
- Using a Non-Executing SET Statement
- Working with Multiple Data Variables
- Retrieving Multiple Data Values
- Using Return Codes with the FIND Method
- Example
- Summary
- Quiz
- 17. Formatting Data
- Overview
- Creating Custom Formats Using the VALUE Statement
- Creating Custom Formats Using the PICTURE Statement
- Managing Custom Formats
- Using Custom Formats
- Creating Formats from SAS Data Sets
- Creating SAS Data Sets from Custom Fomats
- Summary
- Quiz
- 18. Modifying SAS Data Sets and Tracking Changes
- Overview
- Using the MODIFY Statement
- Modifying All Observations in a SAS Data Set
- Modifying Observations Using a Transaction Data Set
- Modifying Observations Located by an Index
- Controlling the Update Process
- Understanding Integrity Constraints
- Placing Integrity Constraints on a Data Set
- Documenting Integrity Constraints
- Removing Integrity Constraints
- Understanding Audit Trails
- Initiating and Reading Audit Trails
- Controlling Data in the Audit Trail
- Controlling the Audit Trail
- Understanding Generation Data Sets
- Initiating Generation Data Sets
- Processing Generation Data Sets
- Summary
- Text Summary
- Using the MODIFY Statement
- Modifying All Observations in a SAS Data Set
- Modifying Observations Using a Transaction Data Set
- Modifying Observations Located by an Index
- Controlling the Update Process
- Placing Integrity Constraints on a Data Set
- Documenting and Removing Integrity Constraints
- Initiating and Terminating Audit Trails
- Controlling Data in the Audit Trail
- Initiating Generation Data Sets
- Processing Generation Data Sets
- Syntax
- Modifying All Observations in a SAS Data Set
- Modifying a Master Data Set Using the BY Statement
- Modifying a Master Data Set Using a Transaction Data Set and an Index
- Controlling the Update Process
- Using PROC DATASETS to Create Integrity Constraints, Generation Data Sets, and Audit Trails
- Using _IORC_ with %SYSRC
- Specifying an Audit Trail File
- Using PROC DATASETS to Rename or Delete Generation Data Sets
- Sample Programs
- Points to Remember
- Text Summary
- Quiz
- 13. Creating Samples and Indexes
- 4. Optimizing SAS Programs
- 19. Introduction to Efficient SAS Programming
- 20. Controlling Memory Usage
- 21. Controlling Data Storage Space
- Overview
- Reducing Data Storage Space for Character Variables
- Reducing Data Storage Space for Numeric Variables
- Compressing Data Files
- Review of Uncompressed Data File Structure
- Compressed Data File Structure
- Deciding Whether to Compress a Data File
- The COMPRESS= System Option and the COMPRESS= Data Set Option
- Example
- Accessing Observations Directly in a Compressed Data Set
- The POINTOBS= Data Set Option
- Example
- The REUSE= System Option and the REUSE= Data Set Option
- Example
- How SAS Compresses Data
- Comparative Example: Creating and Reading Compressed Data Files
- Using SAS DATA Step Views to Conserve Data Storage Space
- DATA Step Views
- Example
- The DESCRIBE Statement
- Creating and Referencing a SAS DATA Step View
- Referencing a Data View Multiple Times in One Program
- Example
- Making Multiple Passes Through Data in a Data View
- Creating Data Views on Unstable Data
- Comparative Example: Creating and Reading a SAS Data View
- Summary
- Quiz
- 22. Using Best Practices
- Overview
- Executing Only Necessary Statements
- Positioning of the Subsetting IF Statement
- Comparative Example: Creating a Subset of Data
- Using Conditional Logic Efficiently
- Comparative Example: Creating Variables Conditionally Using DO Groups
- Comparative Example: Creating Variables Conditionally When Calling Functions
- Using DO Groups Efficiently
- Comparative Example: Creating Data in DO Groups
- Eliminating Unnecessary Passes through the Data
- Using a Single DATA or PROC Step to Enhance Efficiency
- Using a Single DATA Step to Create Multiple Output Data Sets
- Using the SORT Procedure with a WHERE Statement to Create Sorted Subsets
- Using the DATASETS Procedure to Modify Variable Attributes
- Comparative Example: Creating Multiple Subsets of a SAS Data Set
- Comparative Example: Creating a Sorted Subset of a SAS Data Set
- Comparative Example: Changing the Variable Attributes of a SAS Data Set
- Reading and Writing Only Essential Data
- Selecting Observations Using Subsetting IF versus WHERE Statement
- Comparative Example: Creating a Subset of a SAS Data Set
- Other Differences between the IF and WHERE Statements
- Using the WHERE Statement with the OBS= and FIRSTOBS= Options
- Selecting Observations When Reading Data from External Files
- Comparative Example: Creating a Subset of Data by Reading Data from an External File
- Subsetting Variables with the KEEP= and DROP= Statements and Options
- Comparative Example: Creating a Report That Contains Average and Median Statistics
- Comparative Example: Creating a SAS Data Set That Contains Only Certain Variables
- Storing Data in SAS Data Sets
- Avoiding Unnecessary Procedure Invocation
- Summary
- Quiz
- 23. Selecting Efficient Sorting Strategies
- Overview
- Avoiding Unnecessary Sorts
- Using BY-Group Processing with an Index
- Comparative Example: Using BY-Group Processing with an Index to Avoid a Sort
- Using the NOTSORTED Option
- Example
- Using FIRST. and LAST.
- Example
- Using the GROUPFORMAT Option
- Example
- Using the CLASS Statement
- Example
- Comparative Example: Using a BY or CLASS Statement to Avoid a Sort
- Using the SORTEDBY= Data Set Option
- Example
- Using a Threaded Sort
- Calculating and Allocating Sort Resources
- Handling Large Data Sets
- Removing Duplicate Observations Efficiently
- Additional Features
- Summary
- Quiz
- 24. Querying Data Efficiently
- Overview
- Using an Index for Efficient WHERE Processing
- Identifying Available Indexes
- Example: Identifying One Available Index
- Example: Identifying Multiple Available Indexes
- Compound Optimization
- Example: Composite Index That Can Be Used to Optimize Multiple Conditions
- Example: Composite Index That Can Be Used to Optimize One Condition
- Example: Composite Index That Cannot Be Used for Optimizing
- Identifying Conditions That Can Be Optimized
- Estimating the Number of Observations
- Comparing Probable Resource Usage
- Deciding Whether to Create an Index
- Guidelines for Deciding Whether to Create an Index
- Example: Selecting Subsets of Various Sizes from Data Sets of Various Sizes
- Query 1: Small Subset from a Large Data Set
- Query 2: Large Subset from a Large Data Set
- Query 3: Small Subset from a Small Data Set
- Using the Options IDXWHERE= and IDXNAME= to Control Index Usage
- Specifying MSGLEVEL=I to Determine Whether SAS Is Using an Index
- Example: Using IDXWHERE=NO to Prevent Index Usage
- Comparing Procedures That Produce Detail Reports
- Comparing Tools for Summarizing Data
- Comparing Resource Usage across Summarization Tools
- Comparative Example: Displaying Summary Statistics for One Class Variable
- Using PROC MEANS to Display Summary Statistics for Combinations of Class Variables
- Comparing Resource Usage across Three Techniques for Using PROC MEANS
- Using a Basic PROC MEANS Step to Combine All Class Variables
- Example: Displaying Summary Statistics for All Combinations of the Class Variables
- Understanding Types
- Using the TYPES Statement in PROC MEANS to Combine Class Variables
- Example: Using the TYPES Statement in PROC MEANS
- Using the NWAY Option in PROC MEANS to Combine Class Variables
- Example: Using the NWAY Option in Multiple PROC MEANS Steps
- Using the WHERE= Option in PROC MEANS to Combine Class Variables
- Example: Using the WHERE= Option in PROC MEANS
- Comparative Example: Displaying Summary Statistics for Combinations of Class Variables
- Additional Features
- Summary
- Using an Index for Efficient WHERE Processing
- Using an Index for Efficient WHERE Processing
- Identifying Available Indexes
- Identifying Conditions That Can Be Optimized
- Estimating the Number of Observations
- Comparing Probable Resource Usage
- Deciding Whether to Create an Index
- Comparing Procedures That Produce Detail Reports
- Comparing Tools for Summarizing Data
- Using an Index for Efficient WHERE Processing
- Quiz
- 5. Quiz Answer Keys
- 1. Quiz Answer Keys
- Chapter 1: Performing Queries Using PROC SQL
- Chapter 2: Performing Advanced Queries Using PROC SQL
- Chapter 3: Combining Tables Horizontally Using PROC SQL
- Chapter 4: Combining Tables Vertically Using PROC SQL
- Chapter 5: Creating and Managing Tables Using PROC SQL
- Chapter 6: Creating and Managing Indexes Using PROC SQL
- Chapter 7: Creating and Managing Views Using PROC SQL
- Chapter 8: Managing Processing Using PROC SQL
- Chapter 9: Introducing Macro Variables
- Chapter 10: Processing Macro Variables at Execution Time
- Chapter 11: Creating and Using Macro Programs
- Chapter 12: Storing Macro Programs
- Chapter 13: Creating Samples and Indexes
- Chapter 14: Combining Data Vertically
- Chapter 15: Combining Data Horizontally
- Chapter 16: Using Lookup Tables to Match Data
- Chapter 17: Formatting Data
- Chapter 18: Modifying SAS Data Sets and Tracking Changes
- Chapter 19: Introduction to Efficient SAS Programming
- Chapter 20: Controlling Memory Usage
- Chapter 21: Controlling Data Storage Space
- Chapter 22: Using Best Practices
- Chapter 23: Selecting Efficient Sorting Strategies
- Chapter 24: Querying Data Efficiently
- 1. Quiz Answer Keys
The SAS Certification Prep Guide: Advanced Programming for SAS®9 prepares you to take the SAS Advanced Programming exam for SAS®9. New and experienced SAS users who want to prepare for this exam will find this guide to be an invaluable, convenient, and comprehensive resource that covers all of the topics tested on the exam.
Major topics include SQL processing with SAS, the SAS macro language, advanced SAS programming techniques, and optimizing SAS programs. You will also become familiar with the enhancements and new functionality that are available in SAS®9.
The book includes quizzes that enable you to test your understanding of material in each chapter. Additionally, solutions to all quizzes are included at the back of the book.
The SAS Certification Prep Guide: Advanced Programming for SAS®9 is for new or experienced SAS programmers who want to prepare for the SAS Advanced Programming exam for SAS®9.
Candidates must earn the SAS Certified Base Programmer for SAS®9 credential before taking the SAS Advanced Programming exam for SAS®9. The SAS Certification Prep Guide: Base Programming for SAS®9 covers all of the objectives tested on the SAS Base Programming exam for SAS®9, including importing and exporting raw data files, creating and modifying SAS data sets, and identifying and correcting data syntax and programming logic errors.
If you want to test yourself to see if you have the necessary prerequisite base programming knowledge, go to http://support.sas.com/basepractice.
If you are using the SAS 9.1 windowing environment, you can practice what you learn in this book by using sample data in the actual SAS®9 environment. To set up practice data in SAS, select Help
If you are using SAS Learning Edition 4.1, you can practice what you learn in this book by using the SAS windowing environment (the programming approach to SAS) to create the data under the Help menu.
On your desktop, right-click My Computer and select Explore from the pop-up menu.
Navigate to the directory where you installed SAS Learning Edition.
Right-click sas.exe and select Send To and then select Desktop.
A SAS icon now appears on your desktop.
Anytime you want to start the SAS windowing environment, double-click the SAS icon on your desktop.
This is an example of how the general form of SAS code is shown in the book:
General form, basic PROC SQL step to perform a query:
PROC SQL;
SELECT column-1<,...column-n>
FROM table-1|view-1<,...table-n|view-n>
<WHERE expression>
<GROUP BY column-1<, ... column-n>>
<ORDER BY column-1<,... column-n>>;
where
PROC SQL
invokes the SQL procedure
SELECT
specifies the column(s) to be selected
FROM
specifies the table(s) to be queried
WHERE
subsets the data based on a condition
GROUP BY
classifies the data into groups based on the specified column(s)
ORDER BY
sorts the rows that the query returns by the value(s) of the specified column(s).
For example, in the general form above,
SELECT, FROM, WHERE, GROUP BY, and ORDER BY are in uppercase because they must be spelled as shown
column-1, table-1, view-1, and expression are in italics because each represents a value that you supply
<,...column-n> is enclosed in angle brackets because it is optional syntax
table-1 and view-1
are separated by a vertical bar ( | )to indicate that they are mutually exclusive.
The general forms of SAS statements and commands that are shown in this book include only the syntax that you need to know to prepare for the certification exam. For complete syntax, see the appropriate SAS reference guide.
The SAS Certification Practice Exam: Advanced Programming for SAS®9 was designed to help you prepare for the SAS Advanced Programming for SAS®9 exam. This practice exam was constructed to test the same knowledge and skills as the official certification exam. You can access this exam under the SAS Certification category at http://support.sas.com/advpractice. There is a fee for this practice exam.
For information about how to register for the official SAS Advanced Programming for SAS®9 exam, see the SAS Global Certification Program Web site at http://support.sas.com/advpractice.
Other resources might be helpful when learning SAS programming. You can refer to them as needed to enhance your understanding of the material covered in this book. You can access SAS help, documentation, and other resources from your SAS software or on the Web.
From SAS Software | |
|---|---|
Help | SAS 9: Select Help SAS Enterprise Guide: Select Help Enterprise Guide Help. |
Documentation | SAS 9: Select Help SAS Enterprise Guide: Access online documentation on the Web (see On the Web below). |
On the Web | |
|---|---|
Bookstore |
|
Training |
|
Certification |
|
SAS Learning Edition |
|
SAS Global Academic Program |
|
SAS OnDemand |
|
Or
Knowledge Base |
|
Support |
|
Learning Center |
|
Community |
|
-
No Comment