db2 中 sql 查询中的 case when 子句

Question

I have a db2/AS400 database and I'm trying to do the following query:

SELECT *
FROM user
WHERE id IN (
    CASE 
     WHEN 1=1 THEN
        (SELECT id
        FROM user AS userInner
        WHERE userInner.salary < 10)
     ELSE
        (SELECT id
        FROM user AS userInner
        WHERE userInner.salary > 20)
    END
)

The 1=1 condition depends on something else, but it's ok for this simple example. However what I get as an error is the following:

SQL Error [21000]: [SQL0811] Result of SELECT more than one row.

How it would be possible to use case when or other way in order to have a sql_statement condition with multiple results?

Thanks

Answer 1

I don't think you need CASE .
You can do it like this:

SELECT *
FROM user
WHERE id IN (
  SELECT id FROM user
  WHERE (1=1 AND userInner.salary < 10)
     OR (1<>1 AND userInner.salary > 20)
)

Of course you have to replace 1=1 with your actual condition and 1<>1 with its reverse.