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Examples of expressions

You use expressions (expression: Any combination of mathematical or logical operators, constants, functions,

and names of fields, controls, and properties that evaluates to a single value. Expressions can perform

calculations, manipulate characters, or test data.)in many operations in Microsoft Access, including creating

calculated controls, query and filter criteria, default values, validation rules, and macro conditions. Often, theeasiest way to create an expression is to find an example of an expression that is similar to what you want to

create, and then modify it to do what you want.

Examples of expressions used in forms, reports, and data access pages

Examples of manipulating and calculating dates

The following table lists examples of expressions that you can use in calculated controls (calculated control: A

control used on a form, report, or data access page to display the result of an expression. The result is

recalculated each time there is a change in any of the values that the expression is based on.) on forms,

reports, and data access pages (data access page: A Web page, published from Access, that has a connection

to a database. In a data access page, you can view, add to, edit, and manipulate the data stored in the

database. A page can also include data from other sources, such as Excel.) .

Notes

In the ControlSource property of a calculated control, precede the expression with the = operator. On adata access page, you can omit the = operator, and type an alias instead; for example, type WeekNumber:

Format(Now(), "ww").

When you set the Name property of a calculated control in a form or report, or set the ID property of a

calculated control in a data access page, make sure that you use a unique name. Don't use the name or ID of one of the controls you used i n the expression.

In an expression on a form or report, you can use the name of a control or the name of a fiel d in theunderlying records source. In an expression on a data access page, you can use only the name of a field

that's in the data definition of the page.

Examples of manipulating text values

The following table lists examples of expressions that you can use in calculated controls on forms, reports, and

data access pages.

Exp ression Description

=Date() Uses the Date function to display the current date in the form of mm-dd-yyyy,

where mm is the month (1 through 12), dd is the day (1 through 31), and yyyy

is the year (1980 through 2099).

=Format(Now(), "ww") Uses the Format function to display the number of the week of the year the

current date represents, where ww is 1 through 53.

=DatePart("yyyy",[OrderDate])

Uses the DatePart function to display the four-digit year of the value of theOrderDate field.

=DateAdd("y", -10,

[PromisedDate])

Uses the DateAdd function to display a date that is 10 days before the value of

the PromisedDate field.

=DateDiff("d",

[OrderDate],

[ShippedDate])

Uses the DateDiff function to display the variance in days between the values

of the OrderDate and ShippedDate fields.

Expression Description

="N/A" Displays N/A.

=[FirstName]&" "&[LastName] Displays the values of the FirstName and LastName fields separated

by a space.

Page 1 of 10Examples of expressions

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Notes

In the ControlSource property of a calculated control, precede the expression with the = operator. On adata access page, you can omit the = operator, and type an alias instead; for example, type FullName:

[FirstName]&" "& [LastName] .

When you set the Name property of a calculated control in a form or report, or set the ID property of acalculated control in a data access page, make sure to use a unique name. Don't use the name or ID of one

of the controls that you used in the expression.

In an expression on a form or report, you can use the name of a control or field in the underlying record

source. In an expression on a data access page, you can use only the name of a field that's in the datadefinition of that page.

Examples of manipulating arithmetic operations


data access pages.

Notes

In the ControlSource property of a calculated control, precede the expression with the = operator. On a

data access page, you can omit the = operator, and type an alias instead; for example, typeExtendedPrice: [Quantity] * [Price].


calculated control on a data access page, make sure to use a unique name. Don't use the name or ID of one


In an expression on a form or report, you can use the name of a control or the name of a field in the

underlying record source. In an expression on a data access page, you can use only the name of a field that's

in the data definition of the page.

When you use an arithmetic operator ( +, -, *, /) in an expression, and the value of one of the controls in the

expression is Null, the result of the entire expression will be Null. On a form or report, i f some records in

one of the controls that you used in the expression might have a Null value, you can convert the Null valueto zero by using the Nz function; for example:

=Left([ProductName], 1) Uses the Left function to display the first character of the value of the ProductName field.

=Right([AssetCode], 2) Uses the Right function to display the last 2 characters of the value

of the AssetCode field.

=Trim([Address]) Uses the Trim function to display the value of the Address field,

removing any leading or trailing spaces.

=IIf(IsNull([Region]),[City]&" "&

[PostalCode],[City]&" "&[Region]&""& [PostalCode])

Uses the IIf function to display the values of the City and

PostalCode fields if Region is Null; otherwise, it displays the valuesof the City, Region, and PostalCode fields, separated by spaces.


=[Subtotal] + [Freight] The sum of the values of the Subtotal and Freight fields.

=[RequiredDate] -[ShippedDate]

The difference between the values of the RequiredDate and ShippedDatefields.

=[Price] * 1.06 The product of the value of the Pr ice f ield and 1.06 (adds 6 percent to the

Price value).

=[Quantity] * [Price] The product of the values of the Quantity and Price f ields.

=[EmployeeTotal] /

[CountryTotal]

The quotient of the values of the EmployeeTotal and CountryTotal fields.



=Msodsc.Nz([Subtotal]) + Msodsc.Nz([Freight])

Examples of conditional expressions


data access pages.

NotesIn the ControlSource property of a calculated control, precede the expression with the = operator. On a

data access page, you can omit the = operator, and type an alias instead; for example, type

DisplayCountry: IIf(IsNull([Country])," ",[Country]).


calculated control in a data access page, make sure to use a unique name. Don't use the name or ID of one


In an expression on a form or report, you can use the name of a control or the name of a fiel d in the

underlying record source. In an expression on a data access page, you can use only the name of a field that's

in the data definition of the page.

Examples of aggregate and domain aggregate functions

Note You can't use aggregate and domain aggr egate functions in a data access page. Additionally, you can't

use domain aggregate functions in a Microsoft Access project (.adp) (Microsoft Access project: An Access filethat connects to a Microsoft SQL Server database and is used to create client/server applications. A project file

doesn't contain any data or data-definition-based objects such as tables and views.).

Examples of expressions that use aggregate functions

Examples of expressions that use domain aggregate functions


=IIf([Confirmed] = "Yes", "Order

Confirmed", "Order Not Confirmed")

Displays the message "Order Confirmed" if the value of the

Confirmed field is Yes; otherwise, it displays the message "Order

Not Confirmed."

=IIf(IsNull([Country])," ", [Country]) Displays an empty string if the value of the Country field is Null;

otherwise, it displays the value of the Country field.

=IIf(IsNull([Region]),[City]&" "& [PostalCode], [City]&" "&[Region]&" "

&[PostalCode])

Display the values of the City and PostalCode fields if Region isNull; otherwise, it displays the values of the City, Region, and

PostalCode fields.

=IIf(IsNull([RequiredDate] -[ShippedDate]), "Check for a missing

date", [RequiredDate]- [ShippedDate])

Display the message "Check for a missing date" if the result of subtracting ShippedDate from RequiredDate is Null; otherwise, it

displays the difference between the values of the RequiredDate

and ShippedDate fields.

Expression Descr iption

=Avg([Freight]) Uses the Avg function to display the average of the values of the Freight control.

=Count([OrderID]) Uses the Count function to display the number of records in the OrderID control.

=Sum([Sales]) Uses the Sum function to display the sum of the values of the Sales control.

=Sum([Quantity] *

[Price])

Uses the Sum function to display the sum of the product of the values of the

Quantity and Price controls.

=[Sales] / Sum([Sales]) * 100

Displays the percentage of sales, determined by dividing the value of the Salescontrol by the sum of all the values of the Sales control.

Note If the control's Format property is set to Percent, don't include the *100.



Notes

In a calculated control, precede the expression with the = operator.

When you set the Name property of a calculated control, make sure you use a unique name. Don't use the

name of one of the controls you used in the expression.

Examples of expressions used in queries and filters

Examples of criteria used to retrieve records

Ranges of values (>, =,


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Text, partial, and matching values

Part of a field's value (Like)

Dates

In(France, Germany, Japan) For a CountryName field, employees living in France or Germany or Japan

Expression Result

"London" For a ShipCity field, orders shipped to London

"London" Or "Hedge End" For a ShipCity field, orders shipped to London or Hedge End

>= "N " For a CompanyName fi eld, orders shipped to companie s whose name starts

with the letters N through Z

L ike "S*" For a Sh ipName field, orders shipped to cu stomers whose name star ts wi th the

letter S (ANSI-89)

L ike "S%" For a Sh ipName field, orders shipped to cu stomers whose name star ts wi th theletter S (ANSI-92)

Right([OrderID], 2) = "99" For an OrderID field, orders with ID values ending in 99

Len([CompanyName]) > Val

(30)

For a CompanyName field, orders for companies whose name is more than 30

characters long

Expression Result

Like "S*" For a ShipName field, orders shipped to customers whose names start with the letter S

(ANSI-89)

Like "S%" For a ShipName field, orders shipped to customers whose names start with the letter S(ANSI-92)

Like "*Imports" For a ShipName field, orders shipped to customers whose names end with the word

"Imports" (ANSI-89)

Like "%

Imports"

For a ShipName field, orders shipped to customers whose names end with the word

"Imports" (ANSI-92)

Like "[A-D]*" For a ShipName field, orders shipped to customers whose names start with A through D(ANSI-89)

Like "[A-D]%" For a ShipName field, orders shipped to customers whose names start with A through D

(ANSI-92)

Like "*ar*" For a ShipName field, orders shipped to customers whose names include the lettersequence "ar" (ANSI-89)

Like "%ar%" For a ShipName field, orders shipped to customers whose names include the letter

sequence "ar" (ANSI-92)

Like "MaisonDewe?"

For a ShipName field, orders shipped to the customer with "Maison" as the first part of itsname and a 5-letter second name in which the first 4 letters are "Dewe" and the last letter

is unknown (ANSI-89)

Like "MaisonDewe_"

For a ShipName field, orders shipped to the customer with "Maison" as the first part of itsname and a 5-letter second name in which the first 4 letters are "Dewe" and the last letter

is unknown (ANSI-92)



A blank field's value (Null or zero-length string)

The result of a domain aggregate function

The result of a subquery as criteria

Expression Result

#2/2/2000# For a ShippedDate field, orders shipped on February 2,

2000 (ANSI-89)

'2/2/2000' For a ShippedDate field, orders shipped on February 2,

2000 (ANSI-92)

Date() For a RequiredDate field, orders for today's date

Between Date( ) And DateAdd("M", 3, Date( )) For a RequiredDate field, orders required between today's

date and three months from today's date

< Date( ) - 30 For an OrderDate field, orders more than 30 days old

Year([OrderDate]) = 1999 For an OrderDate field, orders with order dates in 1999

DatePart("q", [OrderDate]) = 4 For an OrderDate field, orders for the fourth calendar

quarter

DateSerial(Year ([OrderDate]), Month

([OrderDate]) + 1, 1) - 1

For an OrderDate field, orders for the last day of each

month

Year([OrderDate]) = Year(Now()) And Month

([OrderDate]) = Month(Now())

For an OrderDate field, orders for the current year and

month

Expression Result

Is Null For a ShipRegion field, orders for customers whose ShipRegion field is Null (blank)

Is Not Null For a ShipRegion field, orders for customers whose ShipRegion field contains a value

" " For a Fax field, orders for customers who don't have a fax machine, indicated by a zero-length

string value in the Fax field instead of a Null (blank) value

Expression Result

> (DStDev("[Freight]", "Orders") +DAvg("[Freight]", "Orders"))

For a Freight field, orders for which the freight cost rose above themean plus the standard deviation for freight cost

>DAvg("[Quantity]", "Order Details") For a Quantity field, products ordered in quantities above theaverage order quantity

Expression Result

(SELECT [UnitPrice] FROM

[Products] WHERE [ProductName]= "Aniseed Syrup")

For a UnitPrice field, products whose price is the same as the price of

Aniseed Syrup

> (SELECT AVG([UnitPrice])

FROM [Products])

For a UnitPrice field, products that have a unit price above the average

> ALL (SELECT [Salary] FROM

[Employees] WHERE ([Title] LIKE

"*Manager*") OR ([Title] LIKE

"*Vice President*"))

For a Salary field, the salary of every sales representative whose salary

is higher than that of all employees with "Manager" or "Vice President"

in their titles



Examples of expressions used in calculated fields

Manipulate text values

Perform arithmetic operations

Manipulate and calculate dates

Expression Result

FullName: [FirstName] & " " &

[LastName]

Displays in the FullName field the value of the FirstName and

LastName fields, separated by a space

Address2: [City] & " " & [Region] & "

" & [PostalCode]

Displays in the Address2 field the value of the City, Region, and

PostalCode fields, separated by spaces

ProductInitial: Left([ProductName],

1)

Displays in the ProductInitial field the first character of the value in

the ProductName field

TypeCode: Right([AssetCode], 2) Displays in the TypeCode field the last two characters of the value inthe AssetCode field

AreaCode: Mid([Phone], 2, 3) Displays in the AreaCode field the three characters starting with the

second character of the value in the Phone field

Expression Result

PrimeFreight: [Freight] *

1.1

Displays in the PrimeFreight field freight charges plus 10 percent

OrderAmount: [Quantity] *[UnitPrice]

Displays in the OrderAmount field the product of the values in the Quantity andUnitPrice fields

LeadTime: [RequiredDate]

- [ShippedDate]

Displays in the LeadTime field the difference between the values in the

RequiredDate and ShippedDate fields

TotalStock: [UnitsInStock]

+ [UnitsOnOrder]

Displays in the TotalStock field the sum of the values in the UnitsInStock and

UnitsOnOrder fields

FreightPercentage: Sum([Freight]) / Sum

([Subtotal]) * 100

Displays in the FreightPercentage field the percentage of freight charges in eachsubtotal, by dividing the sum of the values in the Freight field by the sum of the

values in the Subtotal field.

The Total row in the design grid (design grid: The grid that you use to design

a query or filter in query Design view or in the Advanced Filter/Sort window. Forqueries, this grid was formerly known as the QBE grid.) must be displayed, and

the Total cell for this field must be set to Expression.

If the Format property of the field is set to Percent, don't include the *100.

SumofUnits: Nz

([UnitsInStock], 0) + Nz

([UnitsOnOrder], 0)

Displays in the SumofUnits field the sum of all units in stock and on order.

When you use an arithmetic operator (+, -, *, /) in an expression and the

value of one of the fields in the expression is Null, the result of the entireexpression will be Null. If some records in one of the fields you used in the

expression might have a Null value, you can convert the Null value to zerousing the Nz function.

Expression Result

LagTime: DateDiff("d", [OrderDate],[ShippedDate])

Display in the LagTime field the number of days between theorder date and ship date



Use SQL and domain aggregate functions

Work with Null values

Use a subquery

Examples of expressions used in update queries

Use expressions such as the following in the Update To cell in the query design grid for the field you want to

update.

YearHired: DatePart("yyyy", [HireDate]) Displays in the YearHired field the year each employee was hired

MonthNo: DatePart("M", [OrderDate]) Displays in the MonthNo field the number of the month

Pri orDate: Dat e( ) - 30 Displ ays in the PriorDat e fiel d the date 30 days pri or to the

current date

Expression Result

Count(*) Uses the Count function to count the number of records in t he query,

including records with Null (blank) fields

FreightPercentage: Sum([Freight]) / Sum([Subtotal]) *

100

Displays in the FreightPercentage field the percentage of freight charges ineach subtotal, by dividing the sum of the values in the Freight field by the

sum of the values in the Subtotal field.

The Total row in the design grid must be displayed, and the Total cell for

this field must be set to Expression.

If the Format property of the field is set to Percent, don't include the*100.

AverageFreight: DAvg

("[Freight]", "[Orders]")

Displays in the AverageFreight field the average discount given on all

orders combined in a totals query

Expression Result

CurrentCountry: IIf(IsNull([Country]), " ",

[Country])

Displays in the CurrentCountry field an empty string if the

Country field is Null; otherwise, it displays the contents of theCountry field

LeadTime: IIf(IsNull([RequiredDate] -

[ShippedDate]), "Check for a missing date",[RequiredDate] - [ShippedDate])

Displays in the LeadTime field the message "Check for a

missing date" if the value of either the RequiredDate orShippedDate fields is Null; otherwise, it displays the

difference

SixMonthSales: Nz([Qtr1Sales], 0) + Nz([Qtr2Sales], 0)

Displays in the SixMonthSales field the total of the values inthe first-quarter and second-quarter sales fields combined,

using the Nz function to convert the Null values to zero first

Expression Result

Category: (SELECT [CategoryName] FROM

[Categories] WHERE [Products].[CategoryID] =[Categories].[CategoryID])

Displays in the Category field the CategoryName if the

CategoryID from the Categories table is the same as theCategoryID from the Products table

Expression Result

"Salesperson" Changes a text value to Salesperson

#8/10/99# Changes a date value to 10-Aug-99




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Examples of expressions used in SQL statements

You can use an expression in many places in an SQL statement, as the following examples show. Expressionsare shown in bold text.

Examples of default value expressions

Examples of macro condition expressions

You can use any expression that evaluates to True/False or Yes/No in a macro condition (condition: Part of the

criteria that a field must meet for searching or filtering. Some conditions must be used with a value; forexample, the field Author with the condition equals with the value Jane. Author equals, by itself, would be

"PN" & [PartNumber] Adds PN to the beginning of each specified part number

[UnitPrice] * [Quantity] Calculates the product of UnitPrice and Quantity

[Freight] * 1.5 Increases freight charges by 50 percent

DSum("[Quantity] *

[UnitPrice]",

"Order Details", "[ProductID]

=" & [ProductID])

Where the Product IDs in the current table match the Product IDs in the

Order Details table, updates sales totals based on the product of Quantity

and UnitPrice

Right([ShipPostalCode], 5) Truncates the leftmost characters, leaving the five rightmost characters

IIf(IsNull([UnitPrice]), 0,[UnitPrice])

Changes a Null value to a zero (0) in the UnitPrice field

Expression Result

SELECT [FirstName], [LastName] FROM[Employees] WHERE [LastName] =

"Davolio";

Displays the values in the FirstName and LastName fieldsfor employees whose last name is Davolio.

SELECT [ProductID], [ProductName] FROM[Products] WHERE [CategoryID] = Forms!

[New Pr oducts]![CategoryID];

Displays the values in the ProductID and ProductNamefields in the Products table for records in which the

CategoryID value matches the CategoryID value specified in

an open New Products form.

SELECT Avg([ExtendedPrice]) AS [Average

Extended Price] FROM [Order DetailsExtended] WHERE [ExtendedPrice] >

1000;

Displays in a field named Average Extended Price the

average extended price of orders for which the value in theExtendedPrice field is more than 1,000.

SELECT [CategoryID],Count([ProductID])

AS [CountOfProductID]

FROM [Products] GROUP BY [CategoryID]HAVING Count([ProductID]) > 10 ;

Displays in a field named CountOfProductID the total

number of products for categories with more than 10

products.

Expression Default field value

1 1

"MT" MT

"New York, N.Y." New York, N.Y. (note that you must enclose the value in quotes if it includes punctuation)

" " Zero-length string

Date( ) Today's date

=Yes Yes d isp layed in the loca l l anguage of the computer .



incomplete.) . The macro will be executed if the condition evaluates to True (or Yes).

Tip

To cause Microsoft Access to temporarily ignore an action (action: The basic building block of a macro; a self-

contained instruction that can be combined with other actions to automate tasks. This is sometimes called a

command in other macro languages.) , enter False as a condition. Temporarily ignoring an action can be helpful

when you are trying to find problems in a macro.

Use this expression To carry out the action if

[C ity] ="Paris " Pari s is t he Cit y val ue in the field on the form from which the macrowas run.

DCount("[OrderID]", "Orders")>35 There are more than 35 entries in the OrderID field of the Orders

table.

DCount("*", "Order Details","[OrderID]=Forms![Orders]!

[OrderID]")>3

There are more than three entries in the Order Details table for whichthe OrderID field of the table matches the OrderID field on the Orders

form.

[ShippedDate] Between #2-Feb-2001# And #2-Mar-2001#

The value of the ShippedDate fiel d on the form from which the macrois run is no earlier than 2-Feb-2001 and no later than 2-Mar-2001.

Forms![Products]![UnitsInStock]100

The value in the Country field on the form from which the macro isrun is UK, and the value of the TotalOrds field on the SalesTotals form

is greater than 100.

[Country] In ("France", "Italy",

"Spain") And Len([PostalCode])5

The value in the Country field on the form from which the macro is

run is France, Italy, or Spain, and the postal code isn't five characters

long.

MsgBox("Confirm changes?",1)=1 You click OK in a dialog box in which the MsgBox function displays"Confirm changes?". If you click Cancel in the dialog box, Microsoft

Access ignores the action.



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