How to get the column value based on the substitution string in APEX Interactive grid? query?

Hello,

I have to pass the dynamic hidden item value in some columns in APEX Interactive grid.

to_char(&P1_ITEM)

P1_ITEM -> YR_2020 (YR_2020 is column name in the table, column value = 1000)

If I pass the :P1_ITEM in the query, I am getting the item string in the report. How to get the column value(1000) instead of the item string(YR_2020)?

CASE WHEN P1_ITEM = 'YR_2021' then YR_2021

else &P1_ITEM

My else part is not working.

Any help is greatly appreciated.

Thanks