SQL Aggregate

SQL Aggregate Functions

SQL aggregate functions are functions that perform a calculation on a set of values and return a single value. These functions are commonly used with the SELECT statement to compute summaries of data in a database. Here are some of the most commonly used SQL aggregate functions:

1. COUNT(): Returns the number of rows that match a specified condition.




SELECT COUNT(*) FROM table_name;
SELECT COUNT(column_name) FROM table_name WHERE condition;

2. SUM(): Returns the sum of values in a numeric column.




SELECT SUM(column_name) FROM table_name WHERE condition;




3. AVG(): Returns the average of values in a numeric column.




SELECT AVG(column_name) FROM table_name WHERE condition;




4. MIN(): Returns the minimum value in a column.




SELECT MIN(column_name) FROM table_name WHERE condition;




5. MAX(): Returns the maximum value in a column.




SELECT MAX(column_name) FROM table_name WHERE condition;




These functions can also be used together with the GROUP BY clause to perform aggregate calculations on groups of rows. For example:




SELECT column_name, SUM(sales) FROM table_name GROUP BY column_name;

This would return the sum of sales for each unique value in the column_name column.