Cannot convert null to timestamp

[ericOnline]

Hello,

I have a column of timestamps in Unix format. Many of the values are null. I don't want to drop nulls because the records they pertain to are critical. 

How do I handle these nulls and still convert this column to a timestamp using a Custom Column with the following code?:

#datetime(1970, 1, 1, 0, 0, 0) + #duration(0, 8, 0,[unixTimestampColumn]/1000)

 Thank you

[ericOnline]

UPDATE1: 

- I first replaced all nulls with 0. Thid did not work.

- I then replaced all nulls with 000000000000 and even though the column still showed "0", the conversion worked.

NEXT QUESTION:

- I now have a bunch of values with 1/1/1970 (the beginning of Unix epoch).

- What are some ideas for hiding these values in the visualization? 

  - For example: I don't want the user to see "1/1/1970" as an option in any date slicers.

(Reminder: I can't just drop these records because other columns are critical).

Thank you

[amitchandak · Accepted solution]

@ericOnline, try how

if [unixTimestampColumn] is null, then null else #datetime(1970, 1, 1, 0, 0, 0) + #duration(0, 8, 0,[unixTimestampColumn]/1000)