Merge pull request #10 from lucasmrl/aggregate-functions

Added Basic Aggregate Functions

Author: zernonia

content/sql/basic-aggregate-functions.md

@@ -0,0 +1,44 @@
+---
+title: Basic Aggregrate Functions
+description: Set of functions to perform calculation on a set of values. The return is a single summary value. (Except for "round()")
+author: lucasmrl
+github: https://github.com/lucasmrl/
+---
+
+## Basic Aggregate Functions
+
+`max()`
+```sql
+select max(column_name)
+from table_name;
+```
+
+`min()`
+```sql
+select min(column_name)
+from table_name;
+```
+
+`avg()`
+```sql
+select avg(column_name)
+from table_name;
+```
+
+`sum()`
+```sql
+select sum(column_name)
+from table_name;
+```
+
+`count()` - Number of rows where the value is not `NULL`
+```sql
+select count(column_name)
+from table_name;
+```
+
+`round()` - Parameter `integer` specifies the number of decimal places to round the value. All values on "column_name" will be rounded)
+```sql
+select round(column_name, integer)
+from table_name;
+```