How should I achieve NOT EQUAL TO in lookup and restrict the display of the records which are there in lookup table?

Answer:

Lookup does not support != (not equal to) straight out of the box. But we can achieve it. See below example

Lets say, I have a lookup file personal/emp_name1 which has field "emp_name" with values "PQR", "HIG"
I have some data ingested, which shows the name and age of employee, like below

#      age         name2 
1       22          EFG
2       21          ABC
3       25          HIJ
4       20          PQR

Now, we want to display the "name" and "age" of those employees which are not present in lookup table personal/emp_name1

The query would be like below.

(_collector=<name of collector>)
| parse "\"*\", *" as name2,age
| lookup name from personal/emp_name1 on name2=name
| if (isNull(name), "no_name", name) as name1
| where name1="no_name"
| fields - name, name1, _raw

RESULT

#    Time                                  age            name2

1    10/26/2020 15:06:32.276 +0530          22              EFG
2    10/26/2020 15:06:32.276 +0530          21              ABC