1. Succeeding in Business with Microsoft Access 2013
Analyzing Data For Effective
Decision Making
2. Succeeding in Business with Microsoft Access 2013
Chapter Introduction
• Filter data in a Microsoft Office Access 2013
database
– Retrieve and examine only the records you need
– Sort data to rearrange records in a specified order
• Create complex queries
• Explore advanced queries
• Explore queries written in Structured Query
Language
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Tools Covered In This Chapter
• Action queries (update, append, delete, crosstab,
and make-table)
• Aggregate functions (Avg, Max, Min, Sum)
• Calculated field
• Comparison and logical operators
• Crosstab query
• Filter by Form and Filter by Selection
• Find duplicates query
• Find unmatched records query
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Tools Covered In This Chapter (cont’d.)
• Immediate IF (IIF) function
• Parameter query
• Design View
• Select query
• Simple Query Wizard
• SQL commands
• Top Values query
• Wildcard character
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Level 1 Objectives: Organizing and Retrieving
Information from a Database
• Filter and sort data to make it more
meaningful
• Create simple queries to answer business
questions
• Develop queries using comparison criteria and
wildcards
• Verify and print query results
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Filtering and Sorting Data
• Filter
– Restricts data in single table to create temporary
subset of records
– See only certain records in table based on
specified criteria
• Sorting records
– Organizing in particular order or sequence
– Sort records regardless of whether table filtered
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Filtering by Selection
• Tools
– Filter by Selection
• Select particular field in datasheet
• Display only data that matches contents of field
• Specify only one criterion for filter
– Filter by Form
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Filtering by Form
• Specify two or more criteria
• Filter for comparative data
– Use comparison operators
• AND criteria
– Selects records that contain all specified values
• OR criteria
– Selects records that contain any of specified
values
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Sorting Data to Increase Information Content
• Lets you view the information in a variety of ways
• Access sorts records based on primary key values
– Use sorting to change order
• To sort
– Select sort field
• Sort on multiple fields
– Move fields in Datasheet view so that they are
adjacent
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Sorting Data To Increase Information Content
(cont’d.)
• How Access sorts different types of data
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Using Queries to Answer
Business Questions
• Query
– Database object
– Stores criteria for selecting records from one or
more tables based
– Save query
• Use it again
– More powerful than filter
• Display only some fields in table
• Create fields that perform calculations
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Using Queries to Answer
Business Questions (cont’d.)
• Capabilities of Access queries:
– Display selected fields and records from table
– Sort records on one or multiple fields
– Perform calculations
– Generate data for forms, reports, and other queries
– Update data in database
– Find and display data from two or more tables
– Create new tables
– Delete records in table based on one or more criteria
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Using Queries to Answer
Business Questions (cont’d.)
• Select query
– Ask question based on one or more tables in
database
– Result displayed in datasheet
• Called recordset
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Using the Simple Query Wizard
to Create a Query
• Simple query wizard
– Presents list of tables and queries in database
• And fields that they contain
– Select fields from one or more tables
– Wizard creates and displays results
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Including Summary Statistics in a Query for
Data Analysis
• Summary query
– Groups records
– Calculate sum, average, minimum, or maximum
value in each selected field
– Count records in table or query
• Click Summary Options button
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Figure 3.7: Creating a summary query with the Simple Query Wizard
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Creating a Query in Design View
• Select Query window in Design view has two
sections
– Area for field lists at top of window
– Design grid below it
• Add tables for query to top part of window
– Appear as field lists
• Query by example (QBE)
– Typing search value as a criterion
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Creating Queries with
Multiple Criteria
• Most queries involve more than one criterion
• Represent AND criteria
– Enter conditions in same criteria row in query
design grid
• Specify OR criteria
– Use “or” row of query design grid
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Figure 3.10: Setting criteria for the query in Design view
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Specifying Sort Order in Queries
• Query results appear in same order as data
from underlying tables
– Unless specify sort order when designing query
• Sort order determined from left to right
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Running a Query
• Click Run button in the Results group
– Access displays datasheet of records
• Save query
– Save only design
– Not values from tables displayed in results
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Enhancing Query Criteria to Improve Data
Analysis
• Expand criteria by using
– Wildcards
– Comparison operators
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Using Wildcards for Inexact
Query Matches
• Wildcard character
– Placeholder
– Stands for one or more characters
• Comment fields
– Use same keywords throughout comments
– Easily retrieve records later
– Use wildcards when specifying keyword as a query
criterion
• To select records that contain characters before and after
keyword
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Using Wildcards for Inexact Query Matches
(cont’d.)
• Access inserts
– Word “LIKE” for criteria with wildcards quotation
marks around text
• LIKE “*Spanish*”
– Pound signs around dates
• #12/*/2013#
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Using Comparison Operators to Refine Query
Criteria
• Comparison operators
– Compare value in field with range of values in
criterion
• Clear the design grid to create or modify a
query
– Start with same field list but blank grid
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Verifying and Printing
Query Results
• Verify query results before
– Distributing query to others
– Using it as basis for decisions
• Use business knowledge
– Determine whether results adequately answer
question
• Print query datasheet
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Modifying Query Datasheets
• Improve appearance of query or table
datasheet
• Resize column widths in any datasheet
– Double-click line between field names to resize
columns to best fit
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Level 1 Summary
• Use filtering and sorting to change data
display
• Develop queries using
– Simple query wizard
– Design view
• Use comparison operators and wildcards to
make queries more flexible
• Verify query results using business knowledge
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Level 2 Objectives:
Creating More Complex Queries
• Design queries that compare data from more
than one table
• Refine table relationships by specifying the
join type
• Perform calculations in queries
• Customize queries and their results
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Using Queries to Find Duplicate Records
• Duplicates Query Wizard
– Searches for duplicate values in fields
– Improves business operations
– Designed to identify records that contain same
information in particular field
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Using Queries to Find Unmatched Records
• Find Unmatched Query Wizard
– Compares records in two specified tables or
recordsets
– Finds all records in one table or query that have
no related records in second table or query
– Requires that two tables being compared have
common field
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Limiting the Records in the Query Results
• Limiting results to only a few records often
aids analysis
• Top and Bottom Values
– Set a sort order for the field
– Descending to display the records with the highest
values
– Ascending to display the records with the smallest
values
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Using Parameter Values in Queries
• Parameter values
– Phrase usually in form of a question or instruction
– Enclosed in square brackets
– Serves as prompt to user to enter value
– Example
• [Enter a job ID:]
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Analyzing Data from More than One Table
• Data from more than one table required to
answer question
– Combine records from two or more tables
– Display only information needed
• Work in Design View to specify criteria for
selecting records from multiple tables
• Lines between tables link primary key to foreign
key field
– Primary key designated with 1
– Foreign key designated with ∞
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Analyzing Data from More than One Table
(cont’d.)
• Join tables
– Linking of tables using primary and foreign keys
– Established relationship
– Or
• Each table shares field with same or compatible data type
• One join field primary key
• If tables do not include fields that can be joined
– Add one or more extra tables or queries
– Link tables that contain the data
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Analyzing Data from More than One Table
(cont’d.)
• Use queries as source of underlying data for
another query in place of one or more tables
• Create queries based on more than one object
– Should not use any table or query that does not
have common field with at least one of the other
tables or queries
– Otherwise Access displays every combination of
records between two tables
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Refining Relationships with Appropriate Join
Types
• Inner join
– Displays all records in one table that have
corresponding values in common field in another
table
– Records must match before being displayed in
query results
• Outer join
– Displays all records of one table
• Regardless of whether corresponding record is stored in
related table
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Refining Relationships with Appropriate Join
Types (cont’d.)
• Outer join types
– Left
– Right
• Use Join Properties dialog box
– To change join type
– By default, tables are related using inner joins
– Options for outer joins
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Using Logical Operators
to Specify Multiple Conditions
• Logical operators
– Test values that can only be true or false
• Place conditions in separate fields in same
criteria row of design grid
– All conditions in row must be met to select record
• NOT logical operator
– Excludes values that don’t meet criterion
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Performing Calculations with Queries
• Any information derived from fields in table or
query should be calculated in query
– Rather than included as data in table
• Calculation types
– Predefined
• Compute amounts for groups of records or for all records
combined in query
– Custom
• Perform numeric date and text computations on each record
• Using data from one or more fields
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Calculating Statistical Information
• Aggregate functions
– Mathematic and statistical operations
– Apply to records that meet query’s selection
criteria
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Figure 3.43: Using aggregate functions in a query
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Creating Calculated Fields in a Query
• Expression
– Arithmetic formula for calculation
– Use standard arithmetic operators
– Use parenthesis for complex expressions
• Calculated field
– Add to query design grid
– Type expression
• Expression Builder
– Build complex expressions
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Creating Calculated Fields in a Query (cont’d.)
• Function
– Performs standard calculation
– Returns value
• Date()
– Provides today’s date
• Field properties
– Change format and number of decimal places for
calculated field
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Concatenating in Queries
• Concatenation
– Combining contents of two or more fields
– Operator
• &
– Example
• Name [EmpFirst]& " " & [EmpLast]
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Level 2 Summary
• Use queries to select from more than one table
• Join types
– Inner
– Right outer
– Left outer
• Calculated field types
– Predefined
– Custom
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Level 3 Objectives: Exploring Advanced
Queries and Queries Written in Structured
Query Language
• Calculate and restructure data to improve
analysis
• Examine and create advanced types of queries
• Make decisions in a query using the
immediate IF (IIF) function
• Develop queries using SQL
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Analyzing Query Calculations
• More advanced queries
– Crosstab query
• Most useful for preparing data for further analysis
– Action queries
• Change or move many records in one operation
– Four types of action queries:
• Append, update, delete, and make-table
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Analyzing Query Calculations (cont’d.)
• Crosstab queries
– Special type of totals query
– Perform aggregate function calculations on values
of one database field
– Determine exactly how summary data appears in
results
– Calculate and restructure data
• Analyze it more easily
– Work especially well with time-series data
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Creating a Crosstab Query
• To create:
– Use Design View
• Start with select query that includes numeric values or
summary calculations
– Use the Crosstab Query Wizard
• Guides you through the steps
• Shows samples of how the crosstab results will look
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Modifying Data Using Queries
• Action queries
– Modify data in table
– Add records to or delete records from table
– Create new table
• Backup data before using action query
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Archiving Data with Make-table Queries
• Make-table query
– Creates table from some or all of the fields and
records in existing table or query
– Access does not delete selected fields and records
from existing table
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Adding Records to Tables with Append Queries
• Append query
– Select records from one or more tables by setting
criteria
– Add those records to end of another table
– Selected records also remain in original tables
– Table to which records added must already exist
– Can bring data from another source into database
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Removing Records from Tables with Delete Queries
• Delete query
– Removes information from table
– Based on specified criteria
– All records meeting criteria permanently removed
• Create select query first
– Convert to delete query
• Cascading deletes
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Updating Data with an Update Query
• Update query
– Changes values of data in one or more existing
tables
– Create select query first
• Change type to update query
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Making Decisions in Queries
• IF statement
– Tests condition
– Takes one action if condition true
– Takes another action if condition false
• IIF function
– Make IF decision
– Format
• IIF(condition to test, what to do if true, what to do if
false)
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Customizing Queries Using Structured Query
Language
• Access designed as database management
system (DBMS) for:
– Small businesses
– Or departments within large businesses
• Structured query language
– Common query language of most DBMSs
– Use to query/update/manage relational databases
• Create query in Design View
– Access translates entries and criteria into SQL
statements
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Customizing Queries Using Structured
Query Language (cont’d.)
• View statements by switching from Design
view to SQL view
• SELECT statement defines:
– What data query should retrieve from database
– How it should present data
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Exploring the Components
of an SQL Query
• Keywords
– Use to construct SQL statements
• Most developers place each statement on
separate line
– To make SQL code easy to read
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Creating a Union Query Using SQL
• Union query
– Combine, or unite, the results from two or more
select queries
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Level 3 Summary
• Crosstab and Action queries
• IFF function
• SQL
– Use SQL view to edit SQL directly
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Chapter Summary
• Queries retrieve data from one or more tables
– Action queries update data
– Perform calculations
– Make decisions using IIF function
• SQL
– Used to interact with relational databases
– Use SQL view to view/edit SQL statements
generated by Access
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