Solved

nested query interpretation

Posted on 2010-11-22
9
237 Views
Last Modified: 2012-05-10
Is it true that "Select * From sometable Where idRecord IN(Select numOrder From tblOrders Where....);" - is interpreted litterally by jet as: "Select * From sometable Where idRecord IN(1000,1001,1002,1003,1004,1005,...);" !? - Hence the 'query too long' errors may appear sometimes?
0
Comment
Question by:NNOAM1
  • 7
9 Comments
 
LVL 17

Expert Comment

by:JezWalters
ID: 34186577
If your tblOrders sub-query returns (1000,1001,1002,1003,1004,1005,...), then the simple answer is yes!  :-)
0
 
LVL 17

Expert Comment

by:JezWalters
ID: 34186588
Depending on what you're using the resultant records for (specifically, if you need the recordset to be updatable or not), you can probably improve performance by using a join instead.
0
 
LVL 17

Expert Comment

by:JezWalters
ID: 34186608
Your question doesn't give a complete query so I can't either, but I was thinking along these lines:
SELECT sometable.*
FROM sometable, tblOrder
WHERE sometable.idRecord = tblOrders.numOrder AND
tblOrders....

Open in new window

0
Complete VMware vSphere® ESX(i) & Hyper-V Backup

Capture your entire system, including the host, with patented disk imaging integrated with VMware VADP / Microsoft VSS and RCT. RTOs is as low as 15 seconds with Acronis Active Restore™. You can enjoy unlimited P2V/V2V migrations from any source (even from a different hypervisor)

 
LVL 17

Expert Comment

by:JezWalters
ID: 34186631
... or if you prefer using the JOIN keyword:
SELECT sometable.*
FROM sometable INNER JOIN tblOrder
ON sometable.idRecord = tblOrder.numOrder
WHERE tblOrder....

Open in new window

0
 
LVL 17

Expert Comment

by:JezWalters
ID: 34186661
Access is quite poor at optimising queries that contain sub-queries, and will typically evaluate the sub-query for EVERY record returned by its parent query - even when the sub-query records are identical each time.
0
 

Author Comment

by:NNOAM1
ID: 34186766
The point is - I need the parent query to be updatable!
0
 
LVL 17

Expert Comment

by:JezWalters
ID: 34186779
You should get an updateable query if you use the JOIN keyword (as in id 34186631 above).
0
 
LVL 2

Expert Comment

by:Dinesh Subramanian
ID: 34187217
hi,
the best solution is to use the join query. (as in id 34186631 above).
0
 
LVL 17

Accepted Solution

by:
JezWalters earned 500 total points
ID: 34187228
You could try re-phrasing your query using the EXISTS predicate too, but I doubt you'll get much of a performance difference.

INNER JOIN is your best bet!  :-)
0

Featured Post

The Eight Noble Truths of Backup and Recovery

How can IT departments tackle the challenges of a Big Data world? This white paper provides a roadmap to success and helps companies ensure that all their data is safe and secure, no matter if it resides on-premise with physical or virtual machines or in the cloud.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

When you are entering numbers in a speadsheet, and don't remember what 6×7 is, you just type “=6*7" instead. It works in every cell! This is not so in Access. To enter the elusive 42 in a text box, you have to find a calculator, and then copy the re…
I see at least one EE question a week that pertains to using temporary tables in MS Access.  But surprisingly, I was unable to find a single article devoted solely to this topic. I don’t intend to describe all of the uses of temporary tables in t…
In Microsoft Access, learn how to “cascade” or have the displayed data of one combo control depend upon what’s entered in another. Base the dependent combo on a query for its row source: Add a reference to the first combo on the form as criteria i…
In Microsoft Access, learn different ways of passing a string value within a string argument. Also learn what a “Type Mis-match” error is about.

828 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question