Thanks for your reply.  

For the following query:
sql_execute explain select ps_suppkey from partsupp where ps_partkey in
(select p_partkey from part where p_name like 'rose%')

The execution plan is:
'DBT';'PART';'P_NAME';'RANGE CONDITION FOR INDEXED COLUMN';'     
1376';'*';'';'';''
'DBT';'PARTSUPP';'';'NO STRATEGY NOW (ONLY AT EXECUTION TIME)';'      
211';'';'';'';''
'DBT';'';'';'     RESULT IS COPIED   , COSTVALUE IS';'      
239';'';'';'';''

if it means that the subquery is executed first, then join with
ps_suppkey, why there is no temporary table here?

Or if it means doing a nested loop join between ps_suppkey and
p_partkey, why there is no join strategy?

> I think your second execution plan belongs to an select with 
> subquery, from selects and/or set functions. 
> Those temporary results are shown by the explain command.
> 
It is a query with correlated subquery.  How sapdb handles correlated
query?  I have to stop my query after it executing for two days.  All my
tables are in data cache, and the task state is always running.  I am
wondering what it is doing...I'd be happy to post more details.

Thanks for your help,
-- 
Jenny Zhang
Open Source Development Lab Inc 
15275 SW Koll Parkway - Suite H
Beaverton, OR 97006
(503)626-2455 ext 31

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