What query do you have? Tend line of some numbers would be to determine how your numbers are going, if they R tending up or they are tending down. A query for Tend line would see how difference between two consecutive rows is progressing.
Suppose u have
2
4
1
5
Then 2-4 would be up_Trend
4-1 Would be Down_Trend
1-5 Would be Up_trend
as far as I know.