SQL language change in 11g?

The VBA script, within Microsoft Access 2007, runs up to this SQL script, though strangely even if I comment out the "Is Null" statements:

strSQL = "SELECT DISTINCT IIf(qsptLOCATION.AQUIFER_CODE Like 'PER*',""Perched"",""Ogallala"") AS AQ_CODE, qsptLOCATION.AQUIFER_CODE, qsptLOCATION.LOC_CODE, qsptLOCATION.CLASS, IIf([tblWellInfo]![CP_TBL_V]=""POC"",""Compliance"",IIf([tblWellInfo]![CP_TBL_V]=""POE"",""Exposure"","""")) AS DESIGNATION, IIf(clng(tblWellInfo.SEG_SCR) > 1,""M"","""") AS MULTI_LEVEL, tblWellInfo.PROPERTY INTO tbl_LOCATION " & _
"FROM qsptLOCATION INNER JOIN tblWellInfo ON qsptLOCATION.LOC_CODE = tblWellInfo.WELL_ID " & _
"WHERE (((IIf(qsptLOCATION.AQUIFER_CODE Like 'PER*',""Perched"",""Ogallala"")) Like 'PER*' Or (IIf(qsptLOCATION.AQUIFER_CODE Like 'PER*',""Perched"",""Ogallala"")) Like 'OGA*') " & _
"AND ((qsptLOCATION.LOC_CODE) Not Like '*-F' And (qsptLOCATION.LOC_CODE) Not Like 'FPOP*' And (qsptLOCATION.LOC_CODE) Not Like 'OSO*' And (qsptLOCATION.LOC_CODE) Not Like '*GAL') " & _
"AND ((qsptLOCATION.CLASS) Is Null) AND ((qsptLOCATION.DESCRIPT) Is Null)) OR (((IIf(qsptLOCATION.AQUIFER_CODE Like 'PER*',""Perched"",""Ogallala"")) Like 'PER*' " & _
"Or (IIf(qsptLOCATION.AQUIFER_CODE Like 'PER*',""Perched"",""Ogallala"")) Like 'OGA*') " & _
"AND ((qsptLOCATION.LOC_CODE) Not Like '*-F' And (qsptLOCATION.LOC_CODE) Not Like 'FPOP*' And (qsptLOCATION.LOC_CODE) Not Like 'OSO*' And (qsptLOCATION.LOC_CODE) Not Like '*GAL') " & _
"AND ((qsptLOCATION.CLASS) Is Null) AND ((qsptLOCATION.DESCRIPT) Not Like '*RENAMED*')) " & _
"OR (((IIf(qsptLOCATION.AQUIFER_CODE Like 'PER*',""Perched"",""Ogallala"")) Like 'PER*' Or (IIf(qsptLOCATION.AQUIFER_CODE Like 'PER*',""Perched"",""Ogallala"")) Like 'OGA*') " & _
"AND ((qsptLOCATION.LOC_CODE) Not Like '*-F' And (qsptLOCATION.LOC_CODE) Not Like 'FPOP*' And (qsptLOCATION.LOC_CODE) Not Like 'OSO*' And (qsptLOCATION.LOC_CODE) Not Like '*GAL') " & _
"AND ((qsptLOCATION.CLASS) Not In ('PR','AW','IB','PV','IJ')) AND ((qsptLOCATION.DESCRIPT) Is Null)) OR (((IIf(qsptLOCATION.AQUIFER_CODE Like 'PER*',""Perched"",""Ogallala"")) Like 'PER*' Or " & _
"(IIf(qsptLOCATION.AQUIFER_CODE Like 'PER*',""Perched"",""Ogallala"")) Like 'OGA*') " & _
"AND ((qsptLOCATION.LOC_CODE) Not Like '*-F' And (qsptLOCATION.LOC_CODE) Not Like 'FPOP*' And (qsptLOCATION.LOC_CODE) Not Like 'OSO*' And (qsptLOCATION.LOC_CODE) Not Like '*GAL') " & _
"AND ((qsptLOCATION.CLASS) Not In ('PR','AW','IB','PV','IJ')) AND ((qsptLOCATION.DESCRIPT) Not Like '*RENAMED*')) " & _
"ORDER BY IIf(qsptLOCATION.AQUIFER_CODE Like 'PER*',""Perched"",""Ogallala""), qsptLOCATION.LOC_CODE;"
CurrentDb.Execute strSQL

Edited by: Barry on Aug 9, 2011 11:50 AM

We removed "DISTINCT" from the beginning of the script, which solved the problem. But now we are having other problems with the Access database / SQL pass-through queries. Is there much that has changed with Oracle 11g that the SQL queries must be written differently?