When import table from excel some data were loss. i was try to change field type but i cant solve this error. I have attached an example image to show the problem.
A couple things to try:
The import isn't very smart and when it sees a number value for the field, it makes that field's type a number. Reordering may make it interpret the field as text. Notice that the field containing 'NA' values is interpreted as text. See if the first row contains 'NA'. If so, reordering such that the first rows has text in both fields should force it to interpret both fields as text.
ArcGIS uses Microsoft technology to read Office formats, Excel and Access. The default is to read the first 8 rows to determine column datatypes. Changing this registry key forces the entire table to be read first. The infered datatypes and widths are much more accurate, especially for .csv.
typeGuessRows change to 0