Oracle row count for all tables in schema Oracle Database Tips by Donald BurlesonApril 28, 2015 Counting all of the rows in a schema can require code that actually counts the table rows, and it's hard because rows are constantly being added and deleted from the schema.
When new rows of data are inserted into the table or the values in the indexed columns are changed, the database may have to reorganize the storage of the data to make room for the new rows. This reorganization can take additional toll on DML queries. However, if you expect new rows on a regular basis in any table, you can specify the expected growth for an index. The terminology used for this.
Oracle database performance depends on many factors like resource allocated to the database and the the load on the server. To check database health you can generate AWR report which will show you the resource consumption, load on the database, time and resource consuming slow running queries and many recommendations to tune queries, SGA, PGA and other memory components.
Query 2 - works on Oracle 8i and above. The second query retrieves data from an ordered sub-query table. ROWNUM pseudo-column is used outside the sub-query to restrict the number of rows returned. For Oracle 8i and above, we can use this fashion to get the Top N rows by using a sub-query with ORDER BY clause and rownum function in outer query.
Top 10 Oracle SQL Developer Tips and Tricks December 17, 2013 Marc Sewtz Senior Software Development Manager Oracle Application Express Oracle America Inc.
Thanks for the question, Akash. Asked: October 02, 2006 - 10:48 am UTC. Answered by: Tom Kyte - Last updated: October 09, 2012 - 12:09 pm UTC.
Sometimes we have tasks where we need to use Oracle SQL to select the top 10 rows (or any other number) in our result set. For example, if there are too many results. In this article, we will discover how to select and delete the top 10 rows in Oracle using some examples. Oracle SQL SELECT Let’s start by briefly learning the Oracle SELECT.
Summary: in this tutorial, you will learn how to use Oracle RANK() function to calculate the rank of rows within a set of rows. Introduction to Oracle RANK() function. The RANK() function is an analytic function that calculates the rank of a value in a set of values. The RANK() function returns the same rank for the rows with the same values. It adds the number of tied rows to the tied rank.