![]() ![]() To look up ProductName from a Products table based on the value in the text box, you could create another text box and set its ControlSource property to the following expression: For example, suppose you have an Order Details form based on an Order Details table with a text box called ProductID that displays the ProductID field. You can also use the DLookup function in an expression in a calculated control on a form or report if the field that you need to display isn't in the record source on which your form or report is based. You can use the DLookup function to specify criteria in the Criteria row of a query, within a calculated field expression in a query, or in the Update To row in an update query. Whether you use the DLookup function in a macro or module, a query expression, or a calculated control, you must construct the criteria argument carefully to ensure that it will be evaluated correctly. You may want to use a primary key value for your criteria, such as in the following example, to ensure that the DLookup function returns a unique value: Dim varX As Variant You should specify criteria that will ensure that the field value returned by the DLookup function is unique. If more than one field meets criteria, the DLookup function returns the first occurrence. If no record satisfies criteria or if domain contains no records, the DLookup function returns a Null. Although criteria is an optional argument, if you don't supply a value for criteria, the DLookup function returns a random value in the domain. The DLookup function returns a single field value based on the information specified in criteria. Any field that is included in criteria must also be a field in domain otherwise, the DLookup function returns a Null. ![]() If criteria is omitted, the DLookup function evaluates expr against the entire domain. For example, criteria is often equivalent to the WHERE clause in an SQL expression, without the word WHERE. A string expression used to restrict the range of data on which the DLookup function is performed. It can be a table name or a query name for a query that does not require a parameter. A string expression identifying the set of records that constitutes the domain. If expr includes a function, it can be either built-in or user-defined, but not another domain aggregate or SQL aggregate function. ![]() In expr, you can include the name of a field in a table, a control on a form, a constant, or a function. It can be a string expression identifying a field in a table or query, or it can be an expression that performs a calculation on data in that field. An expression that identifies the field whose value you want to return. The DLookup function syntax has these arguments: You could use the DLookup function in a calculated control to display the ProductName on the same form. However, the ProductName field is in another table, the Products table. The form displays the OrderID, ProductID, UnitPrice, Quantity, and Discount fields. For example, suppose you have a form based on an Order Details table. You can use the DLookup function to display the value of a field that isn't in the record source for your form or report. ![]() Use the DLookup function in a Visual Basic for Applications (VBA) module, a macro, a query expression, or a calculated control on a form or report. In Access desktop databases you can use the DLookup function to get the value of a particular field from a specified set of records (a domain). ![]()
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