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Grouping Data Sets by Week Number of the Month

May 1, 2013 I saw a decent SQL brain teaser this morning in the comp.databases.oracle.server Usenet group.  The OP in the message thread is attempting to summarize data in one of his tables, with the summarizations broken down by month and then the week within that month.  Increasing the challenge, the OP required that the dates defining […]

Grouping Data Sets by Week Number of the Month

May 1, 2013 I saw a decent SQL brain teaser this morning in the comp.databases.oracle.server Usenet group.  The OP in the message thread is attempting to summarize data in one of his tables, with the summarizations broken down by month and then the week within that month.  Increasing the challenge, the OP required that the dates defining […]

Analysis Challenges

April 25, 2013 Roughly 12 years ago I was attempting to analyze customer order changes that were received through electronic document interchange (EDI), specifically X12 830 documents that show order forecasted demand for specific part numbers.  At the time, the EDI data was partially transformed and inserted into an Oracle 8.0.5 database, while that data […]

Analysis Challenges

April 25, 2013 Roughly 12 years ago I was attempting to analyze customer order changes that were received through electronic document interchange (EDI), specifically X12 830 documents that show order forecasted demand for specific part numbers.  At the time, the EDI data was partially transformed and inserted into an Oracle 8.0.5 database, while that data […]

Oracle SQL's MEDIAN Function

Article #3 in my ongoing series covering SQL statistic functions in Oracle Database is now up. The topic is the median:
 
MEDIAN: For When You Don't Really Mean It
 
Median is useful in typifying a data set when the data might be skewed, or in the presence of extreme outliers. For example, the U.S. Census Bureau reports median household income for states and counties so as paint a picture unskewed by the presence of, say, Bill Gates or Warren Buffet living just down the street. To learn more, hit the link.

Standard Deviation and the Mean

I've just put up the second in an ongoing series (I hope!) of articles on Oracle SQL's build-in statistical functions. The topic is standard deviation. The previous one, my first, is on the mean. Here are links to the two:
 
2. STDDEV: Standing Sentinel on Your Data
 
1. AVG: What Does it Mean?

Bitten by a Virtual Column, _OPTIMIZER_IGNORE_HINTS Doesn’t Ignore Hints?

March 9, 2013 I had a couple of spare minutes today, so I tried a couple of experiments with Oracle Database 11.2.0.2 just to see if I could produce some unexpected results. First, I will create a simple database table with two indexes: CREATE TABLE T1 (   N1 NUMBER,   V1 VARCHAR2(20),   D1 […]

Feeling ANSI About Oracle Join Syntax? 2

February 7, 2013 (Back to the Previous Post in the Series) As I have mentioned a couple of times previously, I am not much of a fan of ANSI style joins – I prefer using the classical Oracle join syntax when possible.  I try to keep up with an ERP mailing list, and try to assist with […]

Row Level Security 3 – In Pictures!

<..Part one intro and examples
<….Part two Permissions

I’ve noticed that there has not been a lot of traffic on this series on Row Level Security (data masking) so far – maybe due to how I am presenting the material? So here is a summary to date in picture/diagram format:

Row Level Security Part 2 – permissions

<..Part 1, introduction..
..Part 3 summary in pictures..>

In this second post on the topic of “an introduction to Row Level Security” I want to cover a few things about what permissions you need to implement RLS and some of the consequences. In my introduction in part one I just said my main user has “DBA type Privileges”.

{NB This is all on Oracle V11.2 and I believe everything below is applicable to V10 as well. Also, I should point out that I am not an Oracle security expert – but despite repeatedly saying this, it seems like at least once a year I am asked to improve a system’s security on the grounds of “more than we have now is an improvement”}.