Average sql

Sql count

/*COUNT(column_name) will return the number of rows from the column 
that are not NULL*/
SELECT COUNT(column_name)
FROM table_name;

/*COUNT(*) will return the number of rows from the table*/
SELECT COUNT(*)
FROM table_name;

Sql average

SELECT student_name, avg(notes) FROM student_notes GROUP BY student_name;

How to find average in sql

SELECT FIRST_NAME FROM EMPLOYEES
WHERE SALARY = (SELECT AVG(SALARY) FROM EMPLOYEES);

Similar codes

1 vote298 views2 answers
Postgresql check privileges on schema
SQL
4 votes277 views1 answer
Alter session set nls_date_format
SQL
3 votes284 views2 answers
Update part of a string in mysql
SQL
0 vote266 views1 answer
Sql server port 1434
SQL
0 vote275 views1 answer
Hou to run job from cmd .exe sql server jop
SQL
2 votes253 views1 answer
How to select first row of database sql
SQL
1 vote260 views1 answer
Lpad function in sql oracle
SQL
0 vote275 views1 answer
Query to generate query to drop primary keys or foreign key in ms sql server
SQL
6 votes286 views4 answers
Mysql update set
SQL
1 vote270 views2 answers
Remove space in mysql
SQL