I would do the following:
1. Add a second copy of this table to the report in the Database Expert. When you add a table that is already in the report, Crystal will ask if you want to alias it and then add it with "_1" at the end of the table name. So, if the table name is PersonInfo, you'll see that table and PersonInfo_1.
2. Link from {PersonInfo.PERSON_ID} to {PersonInfo_1.PERSON_ID}. Make the link a Left Outer Join.
3. Edit the Selection Criteria for the report. You'll need to edit the formula instead of just selecting fields. In addition to any other criteria in the formula, you'll have something like the following:
{PersonInfo.PHONE_CODE} = "Home" and
(IsNull({PersonInfo_1.PERSON_ID}) OR
{PersonInfo_1.PHONE_CODE} = "Cell")
Note the parentheses in red - these are required to make this work correctly!
4. Create a formula that looks like the following:
If IsNull({PersonInfo_1.PHONE_NO}) or {PersonInfo_1.PHONE_NO} = "" then
{PersonInfo.PHONE_NO}
else
{PersonInfo_1.PHONE_NO}
-Dell