How to combine fields from attribute table?

[NoayavRee]

Hello, 

I'm currently working on a ArcGIS task, however I'm struggling with an analysis that I want to do. It concerns the following; 

I need to perform an analysis on the thickness of specific sandlayers. I have two files for this; one is a point file with specific boreholes and the other one is a table. I have already combined the two, but I need to figure out in what boreholes the sand thickness is at least 3,5m. However, I only know the height of the bottom and the top of the layer of sand. This means that I need to find a way to somehow select those boreholes in which height between the top layer and bottom layers is >3,5m. I was thinking that I have to some processing by substracting the height of the bottom from the height of the top to see the thickness of the boreholes. However, I can't seem to find the right solution to do this and find out what points are suitable or not. 

Anyone can give me any tips or advise?

Thank you in advance! 

[JohannesLindner]

• start the "Select Layer By Attribute" tool
  
• set the input rows to your layer, selection type to "new selection"
• create a new SQL expression
  
• BOTTOMSAND - TOPSAND >= 3.5
• Apply

[EiLaza]

nvm

[NoayavRee]

Thank you! 

However, I'm not sure what SQL statement should be given. I tried something, but it seems to be wrong. I don't know whether that is cause I have an older version of the program. 

[JohannesLindner]

Try it without the quotes. Just 

layerdikte.BOTTOMSAND - layerdikte.TOPSAND >= 3.5