SQL Joins

If you need to understand SQL Joins then following is the good article.

http://www.oracle-base.com/articles/9i/ANSIISOSQLSupport.php

ALL, ANY and SOME Comparison Conditions in SQL

It is quite possible you could work with Oracle databases for many years and never come across the ALL, ANY and SOME comparison conditions in SQL because there are alternatives to them that are used more regularly.

You can find more info on following links:

• PL/SQL Challenge
• Oracle-Base Article
• Oracle Documentation

I hope this will be quite useful to many developers.

Thanks to PL/SQL Challenge.

Regards,

Sohil Bhavsar

SQL Functions: Calculate difference between columns of current and previous/next row

Hi friends,

How to calculate difference between columns of current and previous/next row?

Let's say, you want to monitor how often products are sold from your store.

i.e. 

You want difference between current and previous SELL_DATE then you can write query as follows:

SELECT TO_CHAR(SELL_DATE, 'DD-MON-YYYY HH24:MI:SS'),
       TO_CHAR(LAG(SELL_DATE) OVER (ORDER BY SELL_DATE), 
       'DD-MON-YYYY HH24:MI:SS') AS SELL_DATE_PREV,
       (SELL_DATE - LAG(SELL_DATE) OVER (ORDER BY SELL_DATE))
       * 24 * 60 * 60 AS DIFF_IN_SECONDS
FROM PRODUCT_SALES
ORDER BY SELL_DATE DESC;

More Info: Oracle - Base : Lag Lead Analytic Functions

Regards,


Sohil Bhavsar

Oracle Application Express 4.0 with ExtJS

Oracle Application Express 4.0 with ExtJS

Oracle Application Express 4.0 with ExtJS is quite interesting book. I feel it will be very helpful to the APEX community.

Because, there are very limited resources available for integration of ExtJS and Oracle APEX and the way the book is written it is very easy to understand the concepts of ExtJS.

APEX team has already integrated jQuery in Oracle APEX 4.0 onwards, so before reading the book I had a mindset that jQuery is better then ExtJS but now I feel for Rich User Experience ExtJs is quite good option and APEX Developmt Team should focus towards that.

Congratulations Mark Lancaster for publishing this book.

Oracle Hidden Columns

Hidden Columns for Tables with Column Objects

When a table is defined with a column of an object type, Oracle adds hidden columns to the table for the object type's leaf-level attributes. Each object-type column also has a corresponding hidden column to store the NULL information for the column objects (that is, the atomic nulls of the top-level and the nested objects).

Link to Oracle Doc

APEX 4.0, now the game begins....

Finally APEX 4.0 is released.

Download APEX 4.0

For which we all are waiting.

Great!!!

Set up Oracle Database 11g Release 2 RAC On Linux Using VMware Server 2 using Tim Hall's instruction

Oracle Database 11g Release 2 RAC On Linux Using VMware Server 2

http://www.oracle-base.com/articles/11g/OracleDB11gR2RACInstallationOnOEL5UsingVMwareServer2.php