SQL Functions Examples - Practical Tutorial

Aggregate Functions

Aggregate functions perform calculations on multiple rows and return a single value.

They are commonly used for summarizing data in reports and analytics.

• SUM(): Adds up numeric values.
• COUNT(): Counts rows or non-null values.
• AVG(): Calculates average value.
• MIN() and MAX(): Find minimum and maximum values.

Scalar Functions

Scalar functions operate on a single value and return a single value.

They are useful for formatting, converting, or performing calculations on individual data points.

• UPPER() and LOWER(): Change text case.
• ROUND(): Round numeric values.
• LENGTH(): Get length of a string.
• NOW(): Returns current date and time.

String Functions

String functions help manipulate text data by extracting, concatenating, or modifying strings.

• CONCAT(): Combine multiple strings.
• SUBSTRING(): Extract part of a string.
• TRIM(): Remove leading and trailing spaces.

Date Functions

Date functions allow you to work with date and time values, extracting parts or performing calculations.

• NOW(): Returns current date and time.
• DATE(): Extracts date part from datetime.
• YEAR(), MONTH(), DAY(): Extract respective parts from a date.