The query type determines what records are being grouped together. When merging queries, both queries must be the same type so the same record types can be grouped together. You can merge Dynamic and Static queries together, but not queries of different types.

Alternative Solution:

1. Right click on the query from the main query page.
2. Select Change Category (or Rename).
3. In the Query Type drop-down menu, select the desired type.
4. Click OK.
5. Repeat this process for each query that needs to be changed.

Note: Some queries can not be changed into other types. For example, it is not possible to change a Gift query into a Constituent query.