Solved

MS SQL Syntax

Posted on 2013-12-03
6
176 Views
Last Modified: 2013-12-04
I am trying to delete orphan records where the parent has been deleted (there is no FK defined).

This works:

select * from tblBVMeterReadingErrors a where not exists (Select 0 from tblBVMeterReadings b
where a.BV_Meter_Reading_ID = b.BV_Meter_Reading_ID);

But this doesn't:

delete from tblBVMeterReadingErrors a where not exists (Select 0 from tblBVMeterReadings b
where a.BV_Meter_Reading_ID = b.BV_Meter_Reading_ID);

What is wrong please?
0
Comment
Question by:slimguy
6 Comments
 
LVL 15

Expert Comment

by:gplana
ID: 39693901
Try this way:

delete from tblBVMeterReadingErrors where BV_Meter_Reading_ID NOT IN (Select BV_Meter_Reading_ID from tblBVMeterReadings
where b.BV_Meter_Reading_ID IS NOT NULL);

Open in new window

0
 
LVL 15

Accepted Solution

by:
gplana earned 100 total points
ID: 39693905
Sorry, I made a mistake: please remove the b.  from my previous solution:

delete from tblBVMeterReadingErrors where BV_Meter_Reading_ID NOT IN (Select BV_Meter_Reading_ID from tblBVMeterReadings
where BV_Meter_Reading_ID IS NOT NULL);

Open in new window

0
 
LVL 6

Expert Comment

by:ButlerTechnology
ID: 39693906
Select * from tblBVMeterReadingErros 
where bv_meterReading_ID not in (Select bv_MeterReadingID from tblBVMeterReading)

Delete from tblBVMeterReadingErros 
where bv_meterReading_ID not in (Select bv_MeterReadingID from tblBVMeterReading)

Open in new window


The above code should work.
Tom
0
PRTG Network Monitor: Intuitive Network Monitoring

Network Monitoring is essential to ensure that computer systems and network devices are running. Use PRTG to monitor LANs, servers, websites, applications and devices, bandwidth, virtual environments, remote systems, IoT, and many more. PRTG is easy to set up & use.

 
LVL 15

Expert Comment

by:gplana
ID: 39693927
ButlerTechnology, this is exactly my solution. I just only  add a filter to avoid NULL values which some times could cause problems in comparisions inside the NOT IN.
0
 
LVL 9

Expert Comment

by:QuinnDex
ID: 39693943
this should do it for you check you are getting the correct results with the select before using the delete

select * from tblBVMeterReadingErrors where not in(Select 0 from tblBVMeterReadings
where tblBVMeterReadingErrors .BV_Meter_Reading_ID = tblBVMeterReadings.BV_Meter_Reading_ID);

Open in new window




delete from tblBVMeterReadingErrors where not in(Select 0 from tblBVMeterReadings
where tblBVMeterReadingErrors .BV_Meter_Reading_ID = tblBVMeterReadings.BV_Meter_Reading_ID);

Open in new window

0
 

Author Closing Comment

by:slimguy
ID: 39694870
Many thanks, I should have seen that myself - got a mental block last night!
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

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

When you hear the word proxy, you may become apprehensive. This article will help you to understand Proxy and when it is useful. Let's talk Proxy for SQL Server. (Not in terms of Internet access.) Typically, you'll run into this type of problem w…
This article explains how to reset the password of the sa account on a Microsoft SQL Server.  The steps in this article work in SQL 2005, 2008, 2008 R2, 2012, 2014 and 2016.
Using examples as well as descriptions, and references to Books Online, show the documentation available for date manipulation functions and by using a select few of these functions, show how date based data can be manipulated with these functions.
Via a live example combined with referencing Books Online, show some of the information that can be extracted from the Catalog Views in SQL Server.

910 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

Need Help in Real-Time?

Connect with top rated Experts

24 Experts available now in Live!

Get 1:1 Help Now