How to Count Unique Items in an Access Query Field?

Counting Unique Entries in an Access Query Field

This guide demonstrates how to accurately count unique values within a specific field of an Access query, addressing common errors encountered by users. The solution involves a two-query approach:

Step 1: Isolating Unique Entries

First, construct a subquery to extract the unique values from your target field. Let's assume your field is named "Name" and your table is "table1." The subquery would be:

<code class="language-sql">SELECT DISTINCT Name FROM table1</code>

This query returns only the unique "Name" entries.

Step 2: Counting the Unique Entries

Next, create the main query to count the results from the subquery. This query uses the subquery as its data source:

<code class="language-sql">SELECT Count(*) AS UniqueNameCount
FROM (SELECT DISTINCT Name FROM table1)  AS UniqueNames;</code>

The Count(*) function counts all rows returned by the subquery (which are, by definition, unique). The result is assigned the alias UniqueNameCount.

Step 3: Executing the Query

Run this revised query. The result will accurately reflect the number of unique entries in the "Name" field. For the example provided, the expected output is:

<code>4 row(s)</code>

Consult the linked Access documentation for more detailed information on working with distinct values and aggregate functions in Access queries.

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