FieldId not returned in changelog

Archana Singh_xv1nvr

We are using Jira Rest Apis to fetch issues and related changeLog for the issue. Please refer to the attached response. We have noticed that sometimes fieldId is not returned under changelog >histories>items->. My request looks like below -
https://jira.infusionsoft.com:443/rest/api/2/search?fields=%2Aall&expand=changelog%2CversionedRepresentations

Also what's the difference between field and fieldId? Is the value suppose to be same in both the fields?

Also am not referring to custom field, I have seen fieldId not returned for Description field (every issue has this field). 

Check the response below 

```

"startAt" : 0,
"histories" : [
{
"id" : "1016529",
"items" : [
{
"fieldtype" : "jira",

"from" : null,

"to" : null,
"fromString" : "Custom Statistics Widget Calculates first 10k rows only",

"toString" : "Custom Statistics Widget",

"field" : "description"
}
],

```

Nic Brough -Adaptavist-

The field id for Description is "description".  Only custom fields have numeric field ids, and those are their unique immutable number in the database.  "Field" usually means "current name of the field" (which can be changed)