>Try
>

>SELECT tow.* FROM tow
>	INNER JOIN inhistory ih ON tow.child_id = ih.child_id 
>	WHERE tow.towid > 0 AND tow.vehi_id > 0 AND canccode = '    '
>			AND 
>                (ih.child_id IN ('<<lcchild_id>>', '<<lcParent_Id>>')
>		 OR ih.parent_id IN ('<<lcchild_id>>', '<<lcParent_Id>>'))
>

>
>>On systems with hundreds of thousands of records, these two queries take 17 seconds. Can anyone see a way to optimize them without changing the results? It's a strange query which was modified in the past to add the >0 section because sqlserver was returning errors without out it.
>>
>>

lcParent_Id = ALLTRIM(NVL(parent_id,''))  && 
>>lcChild_Id = ALLTRIM(NVL(child_id,''))
>>
>>TEXT TO lcSQL NOSHOW PRETEXT 15 TEXTMERGE
>>
>>      SELECT tw.* FROM tow AS tw
>>
>>       INNER JOIN
>>
>>            (SELECT inhistory.child_id FROM inhistory
>>
>>             WHERE  inhistory.child_id = '<<lcchild_id>>'
>>
>>             OR inhistory.parent_id = '<<lcchild_id>>'
>>
>>             OR (LEN(inhistory.child_id)>0 AND inhistory.child_id = '<<lcParent_Id>>')
>>
>>             OR (LEN(inhistory.parent_id)>0 AND inhistory.parent_id = '<<lcParent_Id>>')) qry1
>>
>>      ON tw.child_id = qry1.child_id WHERE tw.towid > 0 AND tw.vehi_id > 0 AND canccode='    '
>>
>>ENDTEXT
>>
>>IF SQLProc("SP",m.lcSQL,,,"cTowCT") > 0 && Return any Tow records
>>
>>      TEXT TO lcSQL2 NOSHOW PRETEXT 15 TEXTMERGE
>>
>>            SELECT qry2.towid, vh.* FROM vhtable as vh 
>>
>>      INNER JOIN
>>
>>            (<<m.lcSQL>>) qry2
>>
>>            ON vh.vehi_id = qry2.vehi_id ORDER BY vh.vehi_id
>>
>>      ENDTEXT
>>
>>      IF SQLProc("SP",m.lcSQL2,,,"cvhtableIn") > 0 && Return the vhtable Records
>>
>>            SELECT cvhtableIn
>>
>>      ENDIF
>>
>>ENDIF

Thanks to you both. I'll give them a try. I think I've been looking at it too long... :o)