Selecting by attributes on a float type does not return any records. Clicking Verify to make sure the expression is correct returns:
The expression was executed successfully, but no records were returned.
Floating point numbers are stored in machine precision. Machine precision stores more significant digits than are shown in the unique values window.
Integer data stores whole numbers, while floating-point data contains numeric values with a decimal portion. Issues may arise if the float item's values are between 0 and 1. These values after the decimal place become lost and the values become truncated.
1. Prepare coverage for editing.
2. Open the Field Calculator on the field to be populated.
3. Define the calculation.
4. Stop Editing and save edits.
Use the Properties of the layer in ArcCatalog to add new items. See Chapter 10 of the "Using ArcMap" tutorial for more information.