Reports & Queries - Source : www.pcsoft-windev-webdev.com

3.3.9 Keeping (or not) the duplicatesThe query editor enables you to keep (or not) the duplicated records (duplicates) in the result of a Selectquery (corresponding SQL keyword: DISTINCT).The duplicates are kept by default.To delete the duplicates, click the "Delete the duplicates" button in the description window of the query.To keep the duplicates, click the "Keep the duplicates" button in the description window of the query.3.3.10 Joins between data filesWhen several data files are used in a Select query, the query editor automatically detects the links describedin the analysis between these data files. These links are called joins in the query editor.For example, the following query selects the order numbers of the orders placed by the customers who live inParis. The ORDERS file and the CUSTOMER file are joined by the CustomerNum item. The query editor automaticallydefines the joins between these two data files.Note: The links between the data files are displayed in the graphic representation of the query only if the linkeddata files are used by the query.By default, the joins are automatically created by the query editor. However, these joins may not correspondto the requested result. You have the ability to modify or delete the joins. These operations are described inthe following paragraphs.To add a join into the current Select query (that already includes a join):1. Select "Edit the join" from the popup menu of the join. The description window of the joins is displayed.2. Click the "Add" button. A window allowing you to define a new join is displayed.Note: The "Modify" button is used to modify the selected join.3. Specify the characteristics of the join to add.4. Validate. The join is automatically added into the query.This enables you to create multiple joins between two data files.Part 2: Query editor 201