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Computer Science & Engineering 2111

Computer Science & Engineering 2111

Lecture 12Sorting, Summarizing and Calculating in Queries

Sorting Results in a Query

Use the Sorting line - Ascending or Descending to sort the resulting Query Table

To sort multiple fields – The computer will apply sort precedence for sorting

fields listed on a query from left to right.

Sorting can be combined with any of the filtering techniques (criteria) we have already discussed.

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Write a query to list the City and State of all clients The list should be sorted in ascending order by State and then by City.

Field City State City

Table Client Client Client

Sort Ascending Ascending

Show x x

Criteria

OR

OR

Query Name: NameSort Tables Required: ClientForeign Keys: None Join Type: None

Major Sort

Minor Sort

The data table

The resulting dynaset

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You have decided to give all clients a 10% break on each charge they have made. Write a query to list the ClientID, each charge amount before the discount, the discount, and the charge amount after the discount .

Field ClientID Amount Discount: [Amount] * 0.10 New Charge: [Amount] – [Discount]

Table Client Charges

Sort

Show x x x x

Criteria

OR

OR

Query Name: DiscountCharges Tables Required: Client/ChargesForeign Keys: ClientID Join Type: Inner

What if we want to create a field in a query that is the result of a calculation?

The resulting dynasetNotice new field names

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To Aggregate fields in a Query use the Group by feature

Use the Group by feature to summarize a field – calculating its average, min, max, sum etc.

Select the group(s) you wish to aggregate - Access will automatically group by the lowest detail level field.

In the desired field(s) select the function (sum, average, etc) using the pull down menu

Group by

Sum

Avg

Min

Max

Count

StDev

Var

First

Last

Expression

Where 7

Query design grid's Total Row options:

Group By: Define the groups you want to perform the calculations for. Aggregate Functions: Sum, Avg, Min, Max etc.

Where: Specify criteria for a field, so only those records that meet this criteria will be included in the aggregates.

Expression: Use if a calculated field is required in the query. Expressions will be calculated AFTER the fields are aggregated.

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Write a query that lists how many payments were made by each Client and their total payments. List the First Name, Last Name, the number of payments made, and the total dollar amount of these payments.

Query Name: PaymentSummary Tables Required: Client/PaymentsForeign Keys: ClientID Join Type: Inner

Field First Name Last Name ClientID Amount

Table Client Client Payments Payments

Total Group by Group by Count Sum

SortShow x x x x

CriteriaOROR

Notice new field names

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The resulting dynaset

The data tables(partial view)

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Write a query to summarize by Client, all of the charges made after 5/1/2008. Add a surcharge of 20% to these charges. List the First Name, Last Name, Original Charge and New Charge.

Query Name: ChargesSummary Tables Required: Client/ChargesForeign Keys: ClientID Join Type: InnerField First Name Last Name Amount ChargeDate New Charge: [SumOfAmount] * 1.20Table Client Client Charges Charges

Total Group by Group by Sum Where Expression

Sort

Show x x x x

Criteria > #5/1/2008#

OR

OR

Notice new field names

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The resulting dynaset

The data tables