Replace a null value after search appending

Hello All, I have a search query as below: index="alpha_all_aal_event" type=twaReport|search callId=0 userId=a2ebd4aa-f91a-4088-8667-60143707c368|fields *|rename eventTime.$date as eventTime|eval eventTime=(eventTime/1000)|append [search index="alpha_all_careport_event" userId=a2ebd4aa-f91a-4088-8667-60143707c368|fields *|rename eventTime.$date as eventTime|eval eventTime=(eventTime/1000)|streamstats min(eventTime) as limit]|table eventTime eventData.preLimiterSplEstimate eventData.postLimiterSplEstimate eventData.twaThreshold limit And the data is shown below : ![alt text][1] The limit column has just a single value min(eventTime) from one of the search queries, and its null everywhere else. I want to replace the null value of limit, with already existing single value in limit. Can someone please help me how to do this, as this is appended search I am not getting the expected results. [1]: /storage/temp/209786-screen-shot-2017-09-08-at-45524-pm.png