This FAQ contains some examples of DLookup syntax used in various places within Access 2000. No 'rocket science', but when I was starting out with Access I often struggled for some time to get this syntax correct.
What does DLookup do?
Retrieves a value from a table, based on another field value taken from a form, report or variable.
Example #1 - Used in a Report
Look up a value into a text box, based on a value in another report field:
Code:
=DLookUp("[FieldToLookup]","tblTableName","[KeyField]=Reports!rptReportName![KeyField]")
Example:
Code:
=DLookUp("[EmployeeName]","tblEmployees","[EmployeeID]=reports!rptEmployeeList![EmployeeID]")
Read as:
Find a record in the tblEmployees table;
with EmployeeID equal to the EmployeeID displayed in the report;
and return the Employee Name from this record
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Example #2 - an unbound text box in a form:
Code:
=DLookUp("[FieldToLookup]","tblTableName","[KeyField]=forms!frmMyFormName![KeyField]")
Example:
Code:
=DLookUp("[ApplicationType]","tblApplications","[ApplicationID]=forms!frmApplications![ApplicationID]")
Read this as:
Find a record in tblApplications;
which has ApplicationID = ApplicationID in the form frmApplications;
return the ApplicationType from this record
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[b]Example #3 - Combine DLookup with Format$[/b]
=Format$(DLookUp("[ReportID]","tblReportNames","[ReportName]=txtReportName"),"\R000")
This returns the value of [ReportID], (which is an integer in my example) and formats it as a string consisting of 'R' followed by three digits, e.g. '3' would be displayed as 'R003'
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[b]Example 4 - Set a visual basic variable equal to a value from a table[/b]
[code]
stStringVariable = DLookup("[ColumnName]", "tblTableName", "[ColumnName2] = 'Value'")
Example: look up the Database Name from a Control table, where:
ParameterValue stores the value to be looked up;
ParameterName stores the name of the value to be looked up;
The table is called tblControl1.
Code:
stDatabaseName = DLookup("[ParameterValue]", "tblControl1", "[ParameterName] = 'DatabaseName'")
NB take care with the single quotes round the text string to be looked up - 'DatabaseName'
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Example 5 - a DLookup which concatenates fields
=DLookUp([EmployeeSurname] & ' ' & [EmployeeForenames], tblEmployees, [EmployeeID] = 1234567)
If there is a record in the table with:
EmployeeID = 1234567
EmployeeSurname = Wilson
EmployeeForenames = John
the DLookup function will return:
John Wilson
Note the use of
& ' ' & to insert a space between the two parts of the name.
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Example #6 - DLookup in a sub-form
Similar to example #2, but you need slightly different syntax:
Code:
=DLookUp("[FieldToLookup]","tblTableName","[FieldName]=forms!frmMainFormName!subfrmSubFormName![FieldName]")
End of FAQ text
