Oracle 12c new features (Part – 2)

Posted on 3 CommentsPosted in Oracle, SQL

We have covered Top N queries and Invisible columns in Oracle 12c New Features (Part – 1) In this article, we will learn: Session-Level Sequences Cascading Truncate DDL Logging Identity Columns Multiple Index 3. Session-Level Sequences: In Oracle 12c the CREATE SEQUENCE has a new clause to specify the scope of the sequence – either […]

Oracle 12c new features (Part – 1)

Posted on 1 CommentPosted in Oracle, SQL

In this article, we will learn the top Oracle 12c new features for developers. Top N Queries: This is a way of limiting the number of rows returned to the first ‘N’ meeting the relevant criteria. For example you might wish to retrieve the top 10 highest paid employees. Before Oracle 12c there were several […]

Order By clause in Oracle : Must Know

Posted on Posted in Oracle, SQL

In this article, we will learn what a developer should know about Order by clause in Oracle. When multiple columns/expressions are specified in the ORDER BY clause, the precedence of sorting is left to right. The ORDER BY clause can order in ascending (ASC) or descending (DESC) sequence, or a mix of both. If ASC […]

PseudoColumns in Oracle

Posted on 2 CommentsPosted in Oracle, SQL

In this article, we will learn PseudoColumns in oracle. A pseudocolumn behaves like a table column, but is not actually stored in the table. You can select from pseudocolumns, but you cannot insert, update, or delete their values. A pseudocolumn is also similar to a function without arguments However, functions without arguments typically return the […]

Reset a sequence in Oracle

Posted on Posted in Oracle, SQL

In oracle, there is no built in commend to reset sequence.So we can look at a work around to reset sequence using a procedure.

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PIVOT in Oracle 11G to Select Rows As Columns

Posted on Posted in Oracle, SQL

In this article, we will learn: how to display rows as columns in oracle. Before 11G, the solution to the pivot problem was with a combination of max and decode but in 11g, with the PIVOT syntax, the same query can be written in a more compact, readable form. Let’s take an example to understand it […]

Difference between Decode and Case in Oracle

Posted on Posted in Oracle, SQL

In this article, we will learn the difference between DECODE and CASE . DECODE and CASE statements in Oracle both provide a conditional construct, of this form: if X = n1 then A1 else if X = n2 then A2 else Z Syntax for Decode in Oracle:

Syntax for Case in Oracle:

Databases before […]