Select Distinct around To_Char function

This is an example of a bigger statement but the syntax is the same:

select 2, to_char(UPDATED_BY  || '|' ||  SETTING_NAME || '|' ||SETTING_NAME)
From gsp.settings

I want the distinct UPDATED_BY and SETTING_NAME

I have tried:

select 2, distinct(to_char(UPDATED_BY  || '|' ||  SETTING_NAME) || '|' ||SETTING_NAME)
From gsp.settings 

I get this message ORA-00936: missing expression 00936. 00000 - "missing expression"

I also tried this:

select 2, to_char(distinct(UPDATED_BY  || '|' ||  SETTING_NAME) || '|' ||SETTING_NAME)
From gsp.settings

it gets the same error

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