Oracle SQL / Ansi SQL

Question

Hey,
one of my colleagues managed to create a SQL-statement (in ansi-sql-syntax) that just blocks the session and gives no response at all.
When I rewrote the statement, it gave results within a second.
It's not quite possible to provide a sample-case, but maybe someone here has an idea why the first statement doesn't work, and the second does?
First:
====
SELECT c.CONTRACTID as ENTITEITID,
v.VASTSTELLINGCODE,
'' as INFO,
v.CAMPAGNE
FROM NFD_CONTRACT c
INNER JOIN NFD_OVK o ON o.OVKID = c.OVKID
INNER JOIN NFD_VSTDEFCMP v ON v.VASTSTELLINGCODE = 'C77' AND v.CLASSIFICATIECODE = o.CLASSIFICATIECODE AND v.CAMPAGNE = o.CAMPAGNE
AND Nfd_Vaststellingen_Pck.NFD_IS_DATUM_VST_VALID('C77',o.CAMPAGNE,'Contract',o.CLASSIFICATIECODE) = 1
INNER JOIN NFD_BETROKKENPSN_CON psn ON c.CONTRACTID = psn.CONTRACTID
INNER JOIN (SELECT a.aangifteid, a.psn_nmr, a.psnrolid, a.oogstjaar,
case when exists (SELECT ENTITEITID FROM NFD_VST_OA04_V vst WHERE a.AANGIFTEID = vst.ENTITEITID) then 1
when exists (SELECT ENTITEITID FROM NFD_VST_OA05_V vst WHERE a.AANGIFTEID = vst.ENTITEITID) then 1
when exists (SELECT ENTITEITID FROM NFD_VST_OA06_V vst WHERE a.AANGIFTEID = vst.ENTITEITID) then 1
else 0
end AS OA_Heeft_E
FROM NFD_AANGIFTE a
WHERE AANGIFTETYPE = 'Oogstaangifte') vst ON psn.PSN_NMR = vst.PSN_NMR AND psn.PSNROLID = vst.PSNROLID
AND o.CAMPAGNE = vst.OOGSTJAAR AND vst.OA_Heeft_E = 1
Second:
======
SELECT c.CONTRACTID as ENTITEITID,
v.VASTSTELLINGCODE,
'' as INFO,
v.CAMPAGNE
FROM NFD_CONTRACT c
,nfd_ovk o
,nfd_vstdefcmp v
,nfd_betrokkenpsn_con psn
,(SELECT a.aangifteid, a.psn_nmr, a.psnrolid, a.oogstjaar,
case when exists (SELECT ENTITEITID FROM NFD_VST_OA04_V vst WHERE a.AANGIFTEID = vst.ENTITEITID) then 1
when exists (SELECT ENTITEITID FROM NFD_VST_OA04M_V vst WHERE a.AANGIFTEID = vst.ENTITEITID) then 1
when exists (SELECT ENTITEITID FROM NFD_VST_OA04S_V vst WHERE a.AANGIFTEID = vst.ENTITEITID) then 1
when exists (SELECT ENTITEITID FROM NFD_VST_OA05_V vst WHERE a.AANGIFTEID = vst.ENTITEITID) then 1
when exists (SELECT ENTITEITID FROM NFD_VST_OA06_V vst WHERE a.AANGIFTEID = vst.ENTITEITID) then 1
else 0
end AS OA_Heeft_E
FROM NFD_AANGIFTE a
WHERE AANGIFTETYPE = 'Oogstaangifte') vst
WHERE o.OVKID = c.OVKID
AND v.VASTSTELLINGCODE = 'C77' AND v.CLASSIFICATIECODE = o.CLASSIFICATIECODE AND v.CAMPAGNE = o.CAMPAGNE
AND Nfd_Vaststellingen_Pck.NFD_IS_DATUM_VST_VALID('C77',o.CAMPAGNE,'Contract',o.CLASSIFICATIECODE) = 1
AND c.CONTRACTID = psn.CONTRACTID
AND psn.PSN_NMR = vst.PSN_NMR AND psn.PSNROLID = vst.PSNROLID
AND o.CAMPAGNE = vst.OOGSTJAAR AND vst.OA_Heeft_E = 1

Answer 1

hey riedelmie,
off course the second statement is different.
I rewrote the query so the inner joins are being replaced by where-clauses with the table-names all in the from-clause.
In the second statement there are two extra when-clauses but they should also be in the first statement (the problem is still there, so data could indeed be different, but the problem is the same)
Tnx.
Greetings,
Dave
Message was edited by:
geysemansdave
added text about the when-clauses