SQL-Reihenfolge von in Union alle Abfrage

Question

Ich habe folgende Abfrage, die folgende Daten produziert unten. Alles, was ich Liste der Benutzer in alphabetischer Reihenfolge und First Record anzeigen möchte, sollte All, All sein.

Abfrage:

SELECT 'All' created_by, 
     'All' Prepby 
FROM dual 
UNION ALL 
SELECT DISTINCT 
     to_char(d.created_by) AS created_by, 
     get_user_name(d.created_by) Prepby 
FROM Hpml_Gp_dtl d 
WHERE d.created_by IS NOT NULL 
ORDER BY 2; 

Answer 1

eine CASE Expression in ORDER BY Gebrauch.

Abfrage

select t.* from (
    select 'All' created_by, 'All' Prepby 
    from dual 
    union all 
    select distinct to_char(d.created_by) as created_by, 
    get_user_name(d.created_by) Prepby 
    from Hpml_Gp_dtl d 
    where d.created_by is not null 
) t 
order by case Prepby when 'All' then 1 else 2 end, Prepby; 

Answer 2

Führen Sie die ORDER BY in einer Unterabfrage:

SELECT 'All' AS created_by, 
     'All' AS Prepby 
FROM DUAL 
UNION ALL 
SELECT * 
FROM (
    SELECT DISTINCT 
     to_char(created_by), 
     get_user_name(created_by) 
    FROM Hpml_Gp_dtl 
    WHERE created_by IS NOT null 
    ORDER BY 2 
)