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I'd like to know what is the best way to select a limited top 'n' of rows from a specific column of a geodatabase file. Currently I use a function in the query builder of the select tool (arcgis10) in model builder which look a lot like the one posted on another item on this site (Select top 5 most items in a geodatabase). It looks like this in the expression of the query builder:

[Join_Count] in(SELECT TOP 9 [Join_Count] FROM spatial_join_geodat ORDER BY [Join_Count] DESC)

With this function I am able get a top n, but if the 9,10,11,12..... rows have the same value also these rows are selected. And sometimes the 9th row has a 0 as value and then all the rows are selected which I don't want. So, how do I limit the number of rows to 9 if this is the case?

Has anyone a solution for this?

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this is just a workaround, but if you don't have a rationale for selecting within feature having the same number of joints, you could replace [join_count] with (n*[join_count]+[FID]). [FID] could of course be any other secondary sorting field, and the value of "n" should be larger than the number of feature in your geodatabase (e.g. n=100000).

(100000*[join_count]+[OID]) in(SELECT TOP 9 (100000*[join_count]+[OID]) FROM spatial_join_geodat ORDER BY (100000*[join_count]+[OID]) DESC)
  • I have tried to do it as you said, but then I get an empty output. This is what used: [Join_Count] in(SELECT TOP 9 (10000*[Join_Count]+ [OBJECTID_1]) FROM spatial_join_geodat ORDER BY [Join_Count] DESC) I don't exactly know what this workaround does and why I get an empty output? – rick Jan 14 '14 at 14:13
  • my suggestion was to build a new field with the same ranking information but with unique value. I am not expert in SQL so you can probably write it without actually creating the new field. But on your code you only replaced one occurrence of [joint_count] : it should also be done after ORDER. – radouxju Jan 14 '14 at 14:29
  • Thank you, it works now, I understand what the workaround does! So, I had to replace all [join_counts]! – rick Jan 14 '14 at 14:31

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