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 vote166 views2 answers
Sql convert date to string yyyy-mm-dd
SQL
-1 vote167 views3 answers
Check table exist postgresql
SQL
0 vote161 views2 answers
Mysql password error create datbase
SQL
0 vote165 views1 answer
How to output a different column name in mysql
SQL
-1 vote159 views2 answers
How to select the lowest values from table per client sql
SQL
0 vote226 views1 answer
Reset a table's identity column and remove test records
SQL
9 votes167 views2 answers
Default number in sql
SQL
2 votes212 views2 answers
Mysql write into table
SQL
19 votes176 views6 answers
What is mySQL
SQL
0 vote171 views1 answer
Java sql connection
SQL