Author: admin
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MIN() Function
The MIN() function is used to retrieve the smallest value from a specified column in a dataset. This function is particularly useful for identifying the lowest scores, minimum sales, or least significant performance indicators. The syntax is simple: SELECT MIN(column_name) FROM table_name WHERE condition;. For example, to find the lowest salary among employees, you would…
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COUNT() Function
The COUNT() function counts the number of rows that meet specific criteria in a dataset. It is versatile and can be used in different forms: COUNT(*) counts all rows, including NULLs, while COUNT(column_name) counts only non-NULL values. The syntax is as follows: SELECT COUNT(*) FROM table_name WHERE condition;. For instance, to count the total number…
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AVG() Function
The AVG() function computes the average (mean) of numeric values in a specified column. This function is invaluable for understanding trends in datasets, particularly when analyzing performance or financial metrics. The syntax for AVG() is similar to that of SUM(): SELECT AVG(column_name) FROM table_name WHERE condition;. For example, to find the average salary of employees…
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SUM() Function
The SUM() function is designed to calculate the total of a numeric column across multiple rows. This function is particularly useful in financial contexts, where organizations often need to know total revenues, expenses, or salaries. The syntax for using SUM() is straightforward: SELECT SUM(column_name) FROM table_name WHERE condition;. For example, if you want to find…
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Common Aggregate Functions
In Oracle, the most commonly used aggregate functions are SUM(), AVG(), COUNT(), MIN(), and MAX(). Each of these functions serves a distinct purpose and can be applied to different types of data. The SUM() function totals numeric values, while AVG() calculates the mean. The COUNT() function counts rows or non-null entries, making it versatile for…
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Definition of Aggregate Functions
Aggregate functions in Oracle Database are special functions that process a set of values and return a single summary value. They are crucial for data analysis, allowing users to derive meaningful insights from large datasets. By performing operations such as summation, averaging, and counting, these functions simplify complex data into understandable summaries. This is particularly…
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Object Oriented
In this chapter, we will discuss Object-Oriented PL/SQL. PL/SQL allows defining an object type, which helps in designing object-oriented database in Oracle. An object type allows you to create composite types. Using objects allow you to implement real world objects with specific structure of data and methods for operating it. Objects have attributes and methods.…
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DBMS Output
In this chapter, we will discuss the DBMS Output in PL/SQL. The DBMS_OUTPUT is a built-in package that enables you to display output, debugging information, and send messages from PL/SQL blocks, subprograms, packages, and triggers. We have already used this package throughout our tutorial. Let us look at a small code snippet that will display all the…
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Date & Time
In this chapter, we will discuss the Date and Time in PL/SQL. There are two classes of date and time related data types in PL/SQL − The Datetime data types are − The Interval data types are − Field Values for Datetime and Interval Data Types Both datetime and interval data types consist of fields. The values of these fields…
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Transactions
In this chapter, we will discuss the transactions in PL/SQL. A database transaction is an atomic unit of work that may consist of one or more related SQL statements. It is called atomic because the database modifications brought about by the SQL statements that constitute a transaction can collectively be either committed, i.e., made permanent to the…