Well you've not given us much to go on... You might as well just google optimisation tips...

Data Quality and Data Profiling software

Take a look at http://dev.mysql.com/tech-resources/articles/hierarchical-data.html, about half-way down the page looks similar to what you're asking.

Data Quality and Data Profiling software

If performance is truely the only thing which is important than write your own code. But really is that all that matters? I think your time is worth a lot more than that. Why not use the regexp tools you have and try it out. My betting is that it will be good enough. But who knows without anything else to go on?

Data Quality Tools and Data Profiling software

Not sure how this differs from your earlier question http://www.codeproject.com/Messages/3527850/Complex-Query.aspx[^] You're looking for running totals.

Data Quality Tools and Data Profiling software

Which database are we using here? SQL Server does have an isnull function. For oracle checkout nvl. And for mysql I found this discussion of ifnull http://forums.mysql.com/read.php?98,198593

Data Quality Tools and Data Profiling software

Are you asking for something as simple as string functions such as SQL Server's Replace()? Depending on which database you're using, I'd google "your_database string functions"...

Data Quality Tools and Decision Tree software

Well it looks like a hierachical query to me. You might want to check out http://dev.mysql.com/tech-resources/articles/hierarchical-data.html

Data Quality and Decision Tree tools

Reymelito If you have an example of an update on two tables I'd be interested in seeing it. Let me have the example or link and I'll have a proper pop at this. From http://dev.mysql.com/doc/refman/5.1/en/subquery-restrictions.html: >>In general, you cannot modify a table and select from the same table in a subquery Which rules out one option... My preferred appoach would still be transactions since it will be much more maintainable/readable. Here's an old thread on that http://www.codeguru.com/forum/showthread.php?t=371117&highlight=auto-commit Cheers Dave

Data Quality Tools

I'd be very reluctant to do this as a single query on a join. My preference would be to use a transaction on mutiple updates (Transactions and Atomic Operations).

Data Quality Tools

I concur. But how many times have we all see stuff like this? I like your mapping table solution, unless this is a one off exercise in which case a case statement will run faster and won't need to be maintained.

Data Quality Solutions

So idea of what databases you're working with would help.

Dave Decision Tree Software

Time can be a real nightmare to handle. Other issues which you might want to think about include: Day-light saving time (esp. around midnight boundaries). Time zones -- don't look applicable in your case, but I worked on a car hire problem which supported pickup/drop off across time zones. Of course, I've not actually answered the original question. Some idea of the data structure/data available might be useful.

You can get the SQL Server Compact runtime from http://www.microsoft.com/downloads/details.aspx?familyid=85e0c3ce-3fa1-453a-8ce9-af6ca20946c3&displaylang=en[^]. There's a readme file on that page, but I think you just need to run the installer -- that's all I did for our platforms here. Dave ---- Data Exploration and Data Profiling Tools

I think I may have misunderstood (esp. due to reference to ColumnB), but replace will do it: SQL> select C from dave; C -------------------------------------------------------------------------------- this is columnA columnA is here SQL> update dave set c = replace(C, 'columnA', 'NewText'); 2 rows updated. SQL> select C from dave; C -------------------------------------------------------------------------------- this is NewText NewText is here SQL> Dave ---- Data Exploration and Data Profiling Tools[^]

You might also want to look at an outer join. I wrote something about this a while back: http://www.citrustechnology.com/blog/20100113

May be of some use. We have recently released a Free tool to check conection strings. It won't debug the TCP/IP stream, but will help you see the database at the other end. http://www.citrustechnology.com/product/data-provider-explorer