SAS Viya: Prepare Data; How to replace missing values in the dataset using Data Step?

[nurShahirah]

Hello SAS community.

I am learning how to clean data using Prepare Data page in SAS Viya. Im using a mock data which I have imported into the CAS library and wanted to replace the missing values inside the dataset with the mode of the column as all the data contains categorical type of data. 

Below is how I wrote my coding using Proc Stdize procedure but it does not work. 

Can anyone help me to provide the solution to this?

[ChrisNZ]

Moved to SAS Viya community.