How to convert timestamp to string in Pentaho Kettle?
Just use the select values step. Convert the data type to a string and specify the mask:

yyyyMMdd

Note the mask is a java simpleDateFormat and you can google that for more details. It is case SENSITIVE.

The mask in PDI is only used for 3 things:


Converting from the real data type to a string
Display purposes when previewing data
Any other time you convert to "text" i.e. CSV output, or bulk loaders.


If you are sending it to a target database as a timestamp then it will be whatever that target database uses as default format.