HowToDoThings.com Oracle

How To Code a Matrix Report in SQL

ndoshi — Wed, 12 Mar 2008 15:45:05 -0500

A matrix report is a grid-like representation of data. It has a row of labels, a column of labels and, in a grid, data related to both row and column. Matrix reports are also called crosstab reports.

A matrix report has one group of data for rows, one group of data for columns, one group of data cross-product and one group of data as the value for cross-product. The cross-product group represents all possible combinations of row and column groups.

Let's take a look at an example. Assume you have a table called Inv_summary. It has three columns: Inv_date, Inv_status and Inv_value. Now, you want to generate a report that shows total value of open and close invoices for each month, for example like below.

MONTH OPEN CLOSE

-------- ------------ ------------

How To Add Day, Hour, Minute, Second to a Date Value in Oracle

ndoshi — Mon, 03 Mar 2008 16:46:14 -0600

Date arithmetic is very common in database application. In Oracle, you can add, subtract and compare DATE columns, but you can not multiply or divide it. Oracle stores century, year, month, day, hour, min and seconds as part of the DATE column.

Now let’s take a look at how to add day/hour/minute/second to a date value. Oracle expects a number constant in date arithmetic as number of days. In other words, you need to convert hour, minute and seconds to fraction of a day and then you can add or subtract that value from a date value. Here are some examples:

How To Use Structured Query Language (SQL)

kakulz — Mon, 25 Feb 2008 13:49:37 -0600

Structured Query Language (SQL) is a computer language for creating database and manipulating data. SQL is an ANSI (American National Standard Institute) standard and is supported by almost all Relational Data Base Management Systems (RDBMS) like Oracle, MySQL, SQLServer, MS Access, PostGreSQL etc. SQL has two parts:

Data Definition Language (DDL): to create, alter, or drop tables and indexes.
Data Manipulation Language (DML): to insert, update, retrieve or delete the data in the tables.

Here's how to use SQL.

How To Get Rid of Duplicate Rows in an Oracle SQL Table

ndoshi — Thu, 31 Jan 2008 11:18:09 -0600

If you are using Oracle Database, a common problem is duplicate rows in tables. Usually this happens when unique constraints are removed during loading. Whatever may be the reason, you can remove duplicate records. Duplicate records have identical values for all columns (OR columns that are part of unique key).

There is more than one way to delete duplicate records. Let's assume Table_A has the following data:

Col1 Col2
------ -------
101 201
102 202
103 203
102 202
104 204
101 201

Let's look at the first method.

How To Use Formatting in Oracle SQL

miniguru — Thu, 25 Oct 2007 14:20:26 -0500

Once you retrieve your data, you should think about how you would like to view it. You can do a lot of formatting in Oracle SQL, which translates into saved time for you. After all who wants dirty data?

Formatting is a presentation issue. It allows you to present the data you have gathered so that it looks good. And as someone once said, "Perception is key." I use the following 8 formatting tricks. There are many more, but the ones below are essential to know.

How To Use Oracle SQL

miniguru — Thu, 20 Sep 2007 14:31:33 -0500

SQL is shorthand for Structured Query Language. Oracle SQL is a language and not an application. It is a language that can be used to communicate with databases. Oracle SQL can be used to query databases and analyze data.

Before you use Oracle SQL, you need to understand what a database is. What is a database? It’s a collection of data stored in an organized fashion. The data is stored as Tables inside of a database. Data within tables are stored as rows. All data within a database is either a column or a row. Vertical data is called a column, and horizontal data is called a row.

Oracle SQL is composed of keywords such as SELECT, FROM, WHERE, GROUP BY, HAVING, and ORDER BY. The 6 keywords mentioned above allow you to query a database and analyze its data.