"Nigel J. Andrews" <[EMAIL PROTECTED]> writes: >> select a."RT_REC_KEY", a."cnxarraycolumn", a."CRC" from >> "CNX_DS_53_SIS_STU_OPT_FEE_TB" a left outer join >> "CNX_DS2_53_SIS_STU_OPT_FEE_TB" b on ( a."RT_REC_KEY" = b."RT_REC_KEY" >> and a."cnxarraycolumn" = b."cnxarraycolumn") where b.oid is null ;
> I suspect you get no results because it's unlikely b.oid will be null. Try "it's impossible for b.oid to be null --- unless a dummy b row is being provided by the LEFT JOIN". I interpret the purpose of the query to be to look for "a" rows that have no matching "b" row. Using OID for this is kind of cute, I guess, since it is guaranteed not-null in a real row; he doesn't have to think about whether any of his regular columns are not-null. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])