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Report Builder
User’s Guide
Left Outer Joins
A left outer join is a join that includes all records in the controlling table regardless of whether there are any matching records in the related table. Report Builder includes all the records in the controlling table and any records from the related table that match the join field value in the controlling table.
Figure 8–2 illustrates how left outer joins work.
Figure 8–2: Left Outer Joins
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Figure 8–2 shows which records Report Builder includes when you define a left outer join between the Customer and Order tables on the Cust-Num field. The resulting composite table contains all the records from the Customer table and records from the Order table for which there are corresponding customer numbers. Since the composite record contains fields from both tables, when there is no matching order table record, Report Builder fills in the order fields with UNKNOWN values. Notice that there are two composite records for customer number 2 because there are two orders for that customer in the Order table.
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