Use variable as complete search string

[ameyad]

I am trying to create a dashboard. It has two input text fields.
I want to run a search query based on these two inputs.

If input A is null AND input B is null then no search results
If input A is not null AND input B is null then search using only A
If input A is null AND input B is not null then search using only B

If input A is null AND input B is not null then search using both A and B

Following is my query. It returns no results 

Properties.application="xyz.api"
| spath Level 
| search Level!=Verbose AND Level!=Debug
| eval search_condition_fnum=if(len(trim("$text_fnum$"))=0 OR isnull("$text_fnum$"), "", "RenderedMessage=\"*$text_fnum$*\"")
| eval search_condition_fdate=if(len(trim("$text_fdate$"))=0 OR isnull("$text_fdate$"), "", "RenderedMessage=\"*$text_fdate$*\"")
| eval combined_search_condition=mvjoin(mvfilter(search_condition_fnum!="") + mvfilter(search_condition_fdate!=""), " OR ")
| table search_condition_fnum, search_condition_fdate, combined_search_condition
| search [| makeresults | eval search_condition=mvjoin(mvfilter(search_condition_fnum!="") + mvfilter(search_condition_fdate!=""), " OR ") | fields search_condition]

[yuanliu]

It appears to me that you are overthinking the search language.  Assuming that RenderedMessage is already extracted (as is implied in your illustrated code), you can use

roperties.application="xyz.api"
  (RenderedMessage="*$text_fnum$*" AND RenderedMessage="*$text_fdate$*")
| spath Level 
| search Level!=Verbose AND Level!=Debug
| eval combined_search_condition=mvjoin(mvfilter(search_condition_fnum!="") + mvfilter(search_condition_fdate!=""), " OR ")

If you run this on paper, you will see that the wildcards will cause the search to behave as you described.