Functions and instances in SQL

AVG (average) count (count) max (max) min (minimum) SUM (summation) The syntax for applying a function is: selecte "function name" ("Column name") from "table name

1.AVG:Select AVG (Grade) from Table1, return result: Average of Grade column in Table1

2.COUNT:Select COUNT (Distinct Name) from Table1 where grade>60, return result: Table1 grade> 60 and the name does not repeat (distinct) the number of

3.group by: Group, instance: select Name Count (name) from Table1 where count (name) >3 GROUP by Name, return result: Name repeats more than 3 times name to and quantity

4.having: Syntax: Select column name from table name where condition having function,

Example: select name from Table1 GROUP by name has Count (name) >3, return result: Name repeats more than 3 times name

5.join: Table link, example: Select T1. S_name Name,sum (T2. Grade) Z_grade from Student t1,grades T2 where T1. Namw=t2. Name GROUP by T2. Name

Functions and instances in SQL