如何在plsql条件中解决子查询？

Question

Currently, inside a loop, I have:

    IF(R1.CURRENT_STATE_CODE not in (select stvstat_code from stvstat))
        THEN
        v_cur_state := 'FR';
        ELSE
        v_cur_state := R1.CURRENT_STATE_CODE;
        END IF;

This fails because you cannot perform a subquery in a plsql conditional. "subquery not allowed in this context"

How could I accomplish this instead

Answer 1

Why not just set the value in a select ?

select coalesce(max(s.stvstat_code, 'FR'))
into v_cur_state
from stvstat s
where R1.CURRENT_STATE_CODE = s.stvstat_code;

This is an aggregation query with no group by , so it always returns exactly one row. If the where filters out all rows, then the MAX() returns NULL . The COALESCE() then fills in a value in that case.