Solved

Trouble writing query

Posted on 2013-11-07
11
217 Views
Last Modified: 2013-11-08
So I screwed up and overwrote some data that I didn't want to.  Fortunately I have a backup, but I'm having trouble writing the query.

Let's say we have Table1 and Field1 is the one I messed up.  I only messed up about 500 records out of a million.  I only want to restore those 500 because the backup is a little dated.

And let's say the backup is Table1_backup with a Field1.

How would I go about writing this query?  Any ideas?
0
Comment
Question by:hrolsons
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
11 Comments
 
LVL 41

Expert Comment

by:Sharath
ID: 39631215
1. You can truncate the Table1 and reload from Backup table.
2. You can write a MERGE script to join two tables on Primary key and update the records when Field1 from both the tables are not matching.
0
 

Author Comment

by:hrolsons
ID: 39631324
I like your MERGE idea, but not sure how to write the query.
0
 
LVL 9

Assisted Solution

by:guswebb
guswebb earned 50 total points
ID: 39632243
UPDATE Table1 set Table1.Field1=Table1_backup.Field1 where Table1.id = Table1_backup.id and not Table1.Field1=Table1_backup.Field1

This assumes that both Table1 and Table1_backup have a primary key called 'id' upon which you can bind the two together.
0
Windows Server 2016: All you need to know

Learn about Hyper-V features that increase functionality and usability of Microsoft Windows Server 2016. Also, throughout this eBook, you’ll find some basic PowerShell examples that will help you leverage the scripts in your environments!

 
LVL 69

Assisted Solution

by:Scott Pletcher
Scott Pletcher earned 50 total points
ID: 39632365
Do you have some way in the row's data to identity the 500 rows that you want to change vs the rest of the ~1M rows you don't?  If you do, the UPDATE statement itself will be easy to code, given some type of unique column(s) to join the tables on.
0
 

Author Comment

by:hrolsons
ID: 39632424
So in the real database I have this so far:

UPDATE photos_new set photos_new.pic=photos_new_Backup_06_11_2012.pic  
where photos_new.bookmark=photos_new_Backup_06_11_2012.bookmark
and not photos_new.pic=photos_new_Backup_06_11_2012.pic
and photos_new_Backup_06_11_2012.pic is not null;

The last thing I need to throw in is that we can only change the value if:

photos_new.pic is an integer

Can you help me throw that in there?
0
 

Author Comment

by:hrolsons
ID: 39632439
Would it be :

photos_new.pic NOT LIKE '%[^0-9]%'
0
 
LVL 48

Expert Comment

by:PortletPaul
ID: 39632444
??photos_new.pic is an integer

what is the actual data type of photos_new.pic?
e.g.
varchar
decimal
0
 

Author Comment

by:hrolsons
ID: 39632465
It is varchar.  The records that I screwed up I wrote an integer to that field.
0
 
LVL 48

Assisted Solution

by:PortletPaul
PortletPaul earned 400 total points
ID: 39632480
hrolsons's answer should do it then

(ps: I had not seen that comment until after I added mine)

test by running as a select first :)
0
 

Author Comment

by:hrolsons
ID: 39632601
Good suggestion with the Select.  I tried:

select * from photos_new 
where photos_new.bookmark=photos_new_Backup_06_11_2012.bookmark 
and not photos_new.pic=photos_new_Backup_06_11_2012.pic 
and photos_new_Backup_06_11_2012.pic is not null and photos_new.pic NOT LIKE '%[^0-9]%';

Open in new window


And got the error:

Msg 4104, Level 16, State 1, Line 2
The multi-part identifier "photos_new_Backup_06_11_2012.bookmark" could not be bound.
Msg 4104, Level 16, State 1, Line 3
The multi-part identifier "photos_new_Backup_06_11_2012.pic" could not be bound.
Msg 4104, Level 16, State 1, Line 4
The multi-part identifier "photos_new_Backup_06_11_2012.pic" could not be bound.

Open in new window

0
 
LVL 48

Accepted Solution

by:
PortletPaul earned 400 total points
ID: 39632629
try this, I think you forgot the from clause
/* try select first */
SELECT
        *
FROM photos_new_Backup_06_11_2012
   , photos_new
WHERE photos_new.bookmark = photos_new_Backup_06_11_2012.bookmark
        AND NOT photos_new.pic = photos_new_Backup_06_11_2012.pic
        AND photos_new_Backup_06_11_2012.pic IS NOT NULL
        AND photos_new.pic NOT LIKE '%[^0-9]%';

UPDATE
        photos_new
SET
        photos_new.pic = photos_new_Backup_06_11_2012.pic
FROM photos_new_Backup_06_11_2012
WHERE photos_new.bookmark = photos_new_Backup_06_11_2012.bookmark
        AND NOT photos_new.pic = photos_new_Backup_06_11_2012.pic
        AND photos_new_Backup_06_11_2012.pic IS NOT NULL
        AND photos_new.pic NOT LIKE '%[^0-9]%';

Open in new window

0

Featured Post

Windows Server 2016: All you need to know

Learn about Hyper-V features that increase functionality and usability of Microsoft Windows Server 2016. Also, throughout this eBook, you’ll find some basic PowerShell examples that will help you leverage the scripts in your environments!

Question has a verified solution.

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

Suggested Solutions

How to leverage one TLS certificate to encrypt Microsoft SQL traffic and Remote Desktop Services, versus creating multiple tickets for the same server.
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.
Familiarize people with the process of retrieving data from SQL Server using an Access pass-thru query. Microsoft Access is a very powerful client/server development tool. One of the ways that you can retrieve data from a SQL Server is by using a pa…
Via a live example, show how to extract information from SQL Server on Database, Connection and Server properties

726 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