Why? What if the fields are different lengths?

>>While building some compound indexes like the following ALLTR(A)+Alltr(B) name mytag, I found that I can not relate two tables together on the compound index. The table joins together just fine using the two indexes individually, but not when I concatenate them together. I went so far as to copy the concatenated values from one table to the next, reindexed and still the tables will not relate together correctly when the values are concatenated and a relation is set with the compound value.
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>>Anyone have a clue what I'm doing wrong?
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>In general, it's not a good idea to use Alltrim function in compound indexes. Use A+B or upper(A+B) as index expression, where A & B character fields.
>>thanks