Why am I getting null values in my results?

[human96]

I have a search

index="xyz" sourcetype="csv"
| fillnull value="unknownMan" field1 field2 field3 field4
| eventstats dc(field1) as xyz by field2 field3 field4
| table  field1 field2 field3 field4

while running this, i'm getting NULL values in the results?

Please help me with this why NULL values will be coming when there is no NULL values in the events??

[johnhuang]

When you say "NULL" value, I am assuming you mean the value is blank/empty rather than literal.

Try this to set all the empty values to null. 

index="xyz" sourcetype="csv"
| foreach * [eval <<FIELD>>=IF(<<FIELD>>="", NULL(), <<FIELD>>)]
| fillnull value="unknownMan" field1 field2 field3 field4
| eventstats dc(field1) as xyz by field2 field3 field4
| table field1 field2 field3 field4