How do I add a where statement at the end of query for a column that does not have a table to reference from?

select CASE WHEN (to_char(((case when v.trip_order_start_date is null then case when v.manual_start_date is null then t.required_pickup_date else v.trip_order_start_date end else v.trip_order_start_date end + (interval '-1 hours' * ofc.offset)) at time zone 'utc' at time zone 'America/Chicago' + (interval '-1 hours' * ofc.offset)) at time zone 'utc' at time zone 'America/Chicago', 'YYYYMM') to_char((now() at time zone 'utc' at time zone 'America/Chicago' - interval '1' month), 'YYYYMM'))) THEN 'YES' ELSE 'NO' END AS accrual WHERE accrual = 'YES' The problem is there is no table for me to reference the "accrual" column so I get the below error [Code: 0, SQL State: 42703] ERROR: column "accrual" does not exist Position: 10708 [Script position: 10708 - 10715]