Question

I have this statement:

SELECT *
  FROM sgtn
 WHERE sgtn_kun_id IN (SELECT DISTINCT kun_id
                         FROM sgtn, kun
                        WHERE kun.kun_e_mail IN (LONG LIST OF EMAILS)
                              AND sgtn_kun_id = kun_id)

       AND sgtn_strasse IN (SELECT sgtn.sgtn_strasse
                              FROM sgtn
                             WHERE sgtn_kun_id IN (SELECT DISTINCT kun_id
                                                     FROM sgtn, kun
                                                    WHERE kun.kun_e_mail IN (LONG LIST OF EMAILS)
                                                          AND sgtn_kun_id = kun_id)

                             GROUP BY sgtn.sgtn_strasse
                            HAVING COUNT(sgtn_strasse) > 2);

LONG LIST OF EMAILS is i.e.:
‘[e-mail]’,
‘[e-mail]’,
.
.
.
‘[e-mail]’

As you can see I repeat some part of subquerys in this query.

I’m wondering if and how can I replace LONG LIST OF EMAILS. It occurs in my statement twice. Would it be possible to edit this query, so that the mentioned LONG LIST OF EMAILS occurs once?

Answer 1

First, you don’t need to use

IN (SELECT DISTINCT kun_id
    FROM sgtn, kun
    WHERE kun.kun_e_mail IN (LONG LIST OF EMAILS)
    AND sgtn_kun_id = kun_id)

it is enough

IN (SELECT kun_id
    FROM kun
    WHERE kun.kun_e_mail IN (LONG LIST OF EMAILS))

the rows having multiple sgtn_strasse and email in your list can be detected with

select * from (
  SELECT s.*, count(*) over (partition by sgtn_strasse) cnt_strasse
  FROM sgtn s
  WHERE sgtn_kun_id IN (SELECT kun_id
                       FROM kun
                       WHERE kun.kun_e_mail IN (LONG LIST OF EMAILS))
  )
WHERE cnt_strasse > 1;