Hi all,
these two calls display the same results, the inline-select after a
few ms,
the join after 7 sec.
What is the reason for this magnificant difference?
Why is the plan of the join natural und not by IX_LADEMITTEL_LM_NR?

Greetings Christian


SELECT
L.*,
(SELECT D.DO_NR FROM DOSSIER D WHERE D.DO_ID = L.DO_ID) AS DOSSIER
FROM LADEMITTEL L
ORDER BY L.LM_NR

------------------------------------
PLAN (L ORDER IX_LADEMITTEL_LM_NR)
PLAN (D INDEX (PK_DOSSIER))

------------------------------------
Indexed Read:
Dossier:93
Lademittel:96

NonIndexed: 0
------------------------------------
------------------------------------


SELECT
L.*,
D.DO_NR
FROM LADEMITTEL L
left JOIN DOSSIER D ON L.DO_ID = D.DO_ID
ORDER BY L.LM_NR


------------------------------------
PLAN SORT (JOIN (L NATURAL,D INDEX (PK_DOSSIER)))


Indexed Read:
Dossier:112.755

NonIndexed:
Lademittel:112.791

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------------------------------------