SQL | Advanced Functions

SQL (Structured Query Language) offers a wide range of advanced functions that allow you to perform complex calculations, transformations, and aggregations on your data. 

Aggregate Functions

In database management an aggregate function is a function where the values of multiple rows are grouped together as input on certain criteria to form a single value of more significant meaning.

• SUM(): Calculates the sum of values in a column.
• AVG(): Computes the average of values in a column.
• COUNT(): Returns the number of rows or non-null values in a column.
• MIN(): Finds the minimum value in a column.
• MAX(): Retrieves the maximum value in a column.

Conditional Functions

• CASE WHEN: Allows conditional logic to be applied in the SELECT statement.
• COALESCE(): Returns the first non-null value in a list.
• NULLIF(): Compares two expressions and returns null if they are equal; otherwise, returns the first expression.

Mathematical Functions

Mathematical functions are present in SQL which can be used to perform mathematical calculations. Some commonly used mathematical functions are given below:

• ABS(): Returns the absolute value of a number.
• ROUND(): Rounds a number to a specified number of decimal places.
• POWER(): Raises a number to a specified power.
• SQRT(): Calculates the square root of a number.

Advanced Functions in SQL

BIN(): It converts a decimal number to a binary number.

Query:

SELECT BIN(18);

Output:

BINARY(): It converts a value to a binary string.

Query:

SELECT BINARY "GeeksforGeeks";

Output:

COALESCE(): It returns the first non-null expression in a list. 

Query:

SELECT COALESCE(NULL,NULL,'GeeksforGeeks',NULL,'Geeks');

Output:

CONNECTION_ID(): It returns the unique connection ID for the current connection. 

Query:

SELECT CONNECTION_ID();

Output:

CURRENT_USER(): It returns the user name and hostname for the MySQL account used by the server to authenticate the current client. 

Query:

SELECT CURRENT_USER();

Output:

DATABASE(): It returns the name of the default database. 

Query:

SELECT DATABASE();

Output:

IF(): It returns one value if a condition is TRUE, or another value if a condition is FALSE. 

Query:

SELECT IF(200<500, "YES", "NO");

Output:

LAST_INSERT_ID(): It returns the first AUTO_INCREMENT value that was set by the most recent INSERT or UPDATE statement. 

Query:

SELECT LAST_INSERT_ID();

Output:

Query:

SELECT NULLIF(25.11, 25);

Output:

Query:

SELECT NULLIF(115, 115);

Output:

SESSION_USER(): It returns the user name and host name for the current MySQL user. 

Query:

SELECT SESSION_USER();

Output:

SYSTEM_USER(): It returns the user name and host name for the current MySQL user.

Query:

SELECT SYSTEM_USER();

Output:

USER(): It returns the user name and host name for the current MySQL user. 

Query:

SELECT USER();

Output:

VERSION(): It returns the version of the MySQL database. 

Query:

SELECT VERSION();

Output:

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