MySQL Functions

The pre-defined routines that perform a specific task are known as MySQL functions. MySQL functions are a great way to optimize your database and increase its efficiency. MySQL functions are used when data needs to be manipulated. They are responsible to take input parameters, perform the specified operation, and return a value. 

MySQL provides a variety of built-in functions, that includes string functions, numeric functions, date and time functions, and aggregate functions. It also allows users to create their unique functions using any programming language that suits them. In this blog, we will learn about various MySQL functions like string, numeric, date and time, and aggregate. We will also discuss their uses in depth.

MySQL Overview

MySQL is a client-server relational database management system that is free and open source. In today’s big data world, MySQL is one of the most well-known systems. MySQL is frequently referred to as the most popular server, and it is now widely and efficiently used across industries. Anyone dealing with corporate data or basic IT must strive for a basic understanding of MySQL. 

Even people who are unfamiliar with relational database systems can use MySQL to generate quick, sophisticated, and safe distributed database structures. MySQL’s programmable syntax and conventions are also excellent steps into the vast universe of other prominent programming languages and structural database servers.

Types of MySQL Functions

There are various types of MySQL functions that are in-built and offer great techniques for manipulating data. You can check the SQL course for a better understanding. The following are the most common types of functions which are used to operate Mysql data types:

• Numeric Functions: These functions operate on the numeric values data types.
• String Function: This function in MySQL operates on the string data types.
• Date and Time Functions: These functions specifically come into play on date and time data types.
• Aggregate Functions: This function can operate on all the data types in MySQL. 

MySQL Numeric Functions

MySQL functions constitute numeric functions that are used to perform mathematical operations on numeric data types. Below are some commonly used MySQL numeric functions:

• ABS(x): This function returns the absolute value of x.
• CEILING(x): This function returns the smallest integer whose value is greater than or equal to x.
• FLOOR(x): This function returns the largest integer whose value is less than or equal to x.
• ROUND(x): This function returns rounds to the nearest integer and provides the value of x.
• TRUNCATE(a,b): This function returns decimal places truncated to b.
• MOD(x,y): This function returns the remainder of x divided by y.
• POW(a,b): This function returns the value of a raised to the power of b.
• SQRT(x): This function is responsible for returning the square root of x.
• SIGN(x): This function returns the sign of x.

RAND(): This function returns a random floating-point value that can be between 0 and

MySQL String Functions

String functions are the functions used in string data types in MySQL functions. There is a wide range of string functions available in MySQL. The following are the most commonly used string functions:

CONCAT:	This function is responsible to concatenate two or more strings together.
CONCAT_WS:	This function concatenates two or more strings but with a separator in between.
LENGTH:	The length of the string in characters is returned with the help of this function.
SUBSTRING:	A substring from the specified start position with the specified length is returned through this function.
LEFT:	The leftmost characters from the string up to the specified length are returned via this function.
RIGHT:	The rightmost characters from the string up to the specified length are returned via this function.
TRIM:	This function removes leading characters from the string.
UPPER(str):	This function converts the string to uppercase.
LOWER(str):	This function converts the string to lowercase.
REPLACE (from_str,to_str):	This function replaces all occurrences of the from_str with to_str in the string.

The above-mentioned examples are just a few of the many string functions that are available in MySQL.

MySQL Date and Time Functions

MySQL functions also enable date and time data types that allow the user to work on various types of data depending on the date and time. The following are some commonly used functions in date and time data type:

• This function will return the current date and time.
• CURDATE() returns the current date.
• CURTIME() returns the current time.
• DATE() This function extracts the date portion of a date or date time expression.
• TIME() component extracts the time of a date-time expression.
• YEAR() extracts the year from a date or date time expression.
• MONTH() extracts the month from a date or date time expression.
• DAY() extracts the month’s day from a date or date time expression.
• HOUR() extracts the hour from a time or date time expression.
• MINUTE() extracts the minute from a time or date time expression.
• SECOND() extracts the second from a time or date time expression.
• DATE_FORMAT() formats a date or date time value depending on a format string.
• DATE_ADD() adds a time interval to a date or date time expression.
• DATE_SUB() subtracts a specified time interval from a date or date time expression.
• TIMESTAMP() converts a date or date time expression to a Unix timestamp.

MySQL Aggregate Functions

MySQL functions constitute aggregate functions that are responsible for performing calculations on multiple rows in a single column of a table. The following are the most commonly used aggregate functions in MySQL:

• COUNT: The number of rows in a table or the number of rows that meets a specific condition are returned with this aggregate function. 

The following Syntax should be applied: 

COUNT(expression)

Here’s an example:

SELECT COUNT(*) FROM customers;

After you’ve built a “customers” table that provides information about the customers. The above-mentioned query will return a single value, which will be the total number of rows in the customer table.

• SUM: The sum of values in a column is returned with this aggregate function.

The following Syntax should be applied:

SUM(expression)

Here’s an example:

SELECT SUM(amount) FROM sales WHERE date = ‘2023-04-04’;

You’ve established a table called “sales” that holds sales data such as the date and value of the sale. The above-mentioned query will be used, and it will return a single value, April 4th, 2023.

• AVG: This aggregate function is used to return the average value in the column.

The following Syntax should be applied:

AVG(expression)

Here’s an example: 

SELECT AVG(salary) FROM employees;

After building a table called “employees” that contains information on the company’s employees. The query indicated above will be used, and it will return a single value, which will be the employees’ salaries or whatever you have put in the expression field.

• MAX: This aggregate function is responsible to return the maximum value in a column.

The following Syntax should be applied:

MAX(expression)

Here’s an example:

SELECT MAX(price) FROM products;

If you have created a table called “products” that contains information about your company’s products, including their names, prices, and quantities. The query mentioned above will be used and will return the value which will be the highest price of any product.

• MIN: This aggregate function returns the minimum value in a column.

The following Syntax should be applied:

MIN(expression)

Here’s an example:

SELECT MIN(order_total) FROM orders;

If you create a table called “orders” that contains information about your company’s sales orders, including the customer name,  order ID, and order total. The query mentioned right above will be used and will return the single value which will be the smallest order total.

Why MySQL Functions?

MySQL functions prove to be helpful in different scenarios. Following are a few reasons why you might want to use the functions in MySQL:

• Reusability: It allows you to write a block of code that can repeatedly be used throughout the database queries. It saves time in writing code and makes queries more efficient.

• Performance: The functions are optimized for performance by MySQL query optimizer, and result in faster execution time for queries.

• Modularity: The functions are combined with other functions to create more complex queries, making it easier to build complex database applications.

• Customization: To perform specialized operations, it allows you to create custom functions that are not built into MySQL. 

Conclusion

MySQL functions are powerful tools that allow developers to process and manipulate data in a variety of ways. It offers a vast array of built-in functions, and developers can also create custom functions to meet specific business requirements.