Back to Basics – What is the Difference between Selection and Projection?

These concepts are related to the sql statement in oracle and in RDBMS in general. Projection This is a vertical subset of table columns (the select list) , including all rows.It may include one column, two columns or all table columns.Projection answers the question: which columns the query shall return? For example:select empno , ename, … Continue reading Back to Basics – What is the Difference between Selection and Projection?

The Longest SQL Statement I have ever seen !

Below may be the longest SQL statement that I have ever seen. I don't know if it is written by one developer or group of developers and what is the logic behind it? I really don't like this style of writing sql statements. It is very difficult to be functionally understood. Also, it is very … Continue reading The Longest SQL Statement I have ever seen !