Select every nth record in a table or feature class

Summary

To select every nth record in a table using Select by Attributes and, use the modulo function (MOD).

• ArcGIS Pro: Mod

This avoids the use of Python scripting and can be input to the Feature Class to Feature Class tool. Extra modifications can be made to start at a particular record, as well. 

Procedure

Use the following formula:

MOD(OBJECTID+2n-x, n) = 0

• n is the every nth record
• x is the objectid to start  from

A few examples:

For every fourth record, starting at OBJECTID = 1:

• n = 4
• x = 1

MOD(OBJECTID+7,4) = 0

Selects records 1, 5, 9, 13, and so forth.

For every third record, starting at OBJECTID = 2:

• n = 3
• x = 2

MOD(OBJECTID+4,3) = 0

Selects records 2, 5, 8, 11, and so forth.

Note that this formula fails for 2n < x