There are four merge operators: AND, OR, XOR, and SUB. The results of the merged query vary depending on the merge operator you select.

Let's say you have two queries, one of South Carolina residents and another of alumni. In these examples, the circle on the left represents the primary query of South Carolina residents; the circle on the right represents the secondary query of alumni. The shaded portion represents the results of the merged query.

AND:
A record must exist in both queries to be included in the merged query. The merged query using the AND operator consists of alumni who live in South Carolina:

Two overlapping circles with the overlapping region shaded

OR:
Records that exist in either query are included in the merged query. However, records that exist in both queries are present only once in the merged query. The merged query using the OR operator consists of all alumni and all South Carolina residents:

Two overlapping circles. Both circles are completely shaded.

XOR:
Records that exist in the primary query only or in the secondary query only are included in the merged query. The record cannot exist in both queries. The merged query using the XOR operator consists of South Carolina residents who are not alumni and alumni who do not live in South Carolina:

Two overlapping circles with the areas that do not overlap shaded.

SUB:
Records that exist only in the primary query and not in the secondary query are included in the merged query. SUB subtracts records in the secondary query from the primary query; records in the secondary query that are also in the primary query are excluded from the merged query. When you use SUB, carefully consider which query is primary and which is secondary. The merged query using the SUB operator consists of South Carolina residents who are not alumni:

Two overlapping circles. The circle on the left is shaded except where it overlaps the circle on the right.