Question

I have the following query which runs perfectly well on both Oracle and SQL Server 2008 however it doesn’t seem to run on PostgreSQL. The query is intended to return a count of records that match the given criteria. Can someone explain the reason for this and also offer a solution to how this query can be modified to allow it to produce the expected result.

Query:

select count(*) 
from tma_notices 
where TNOT_NOTICE_TYPE ='0400' 
and TNOT_NOTICE_STATUS = 'OK' 
and tnot_notice_id >= 
    (
        select NOTICE_NUM_AT_MIDNIGHT 
        from RWOL_COUNTER_QUERY_TYPE 
        where QUERY_TYPE = 'START_NOTICES_TODAY' 
        and USER_NAME = 'PUBLIC'
    )

UPDATE: This error was caused by unforeseen duplicate records in the PostgreSQL database. Where the duplicates came from needs to be investigated.

Answer 1

It’s pretty clear that the subquery could return a set of rows and the condition tnot_notice_id >= isn’t valid if compared with a set of rows and not with only a single value.

Are you sure that exist a unique record that satisfy your where conditions?

If you want to avoid that behaviour, I suggest you to use tnot_notice_id >= ALL ( subquery )