be used to find the maximum of the distinct values of expr , however, this produces the same result as omitting DISTINCT . 

If there are no matching rows, MAX()  returns NULL . 

This function executes as a window function if over_clause  is present. over_clause  is as described in Section 12.21.2, “Window Function Concepts and Syntax” ; it cannot be used with DISTINCT . 

mysql> SELECT student_name, MIN(test_score), MAX(test_score) FROM student GROUP BY student_name; 

For MAX() , MySQL currently compares ENUM  and SET  columns by their string value rather than by the string’s relative position in the set. This differs from how ORDER BY  compares them. 

• MIN([DISTINCT] expr ) [ over_clause ] 

Returns the minimum value of expr . MIN()  may take a string argument; in such cases, it returns the minimum string value. See Section 8.3.1, “How MySQL Uses Indexes” . The DISTINCT  keyword can be used to find the minimum of the distinct values of expr , however, this produces the same result as omitting DISTINCT . 

If there are no matching rows, MIN()  returns NULL . 

This function executes as a window function if over_clause  is present. over_clause  is as described in Section 12.21.2, “Window Function Concepts and Syntax” ; it cannot be used with DISTINCT . 

mysql> SELECT student_name, MIN(test_score), MAX(test_score) FROM student GROUP BY student_name; 

For MIN() , MySQL currently compares ENUM  and SET  columns by their string value rather than by the string’s relative position in the set. This differs from how ORDER BY  compares them. 

• STD( expr ) [ over_clause ] 

Returns the population standard deviation of expr . STD()  is a synonym for the standard SQL function STDDEV_POP() , provided as a MySQL extension. 

If there are no matching rows, STD()  returns NULL . 

This function executes as a window function if over_clause  is present. over_clause  is as described in Section 12.21.2, “Window Function Concepts and Syntax” . 

• STDDEV( expr ) [ over_clause ] 

Returns the population standard deviation of expr . STDDEV()  is a synonym for the standard SQL function STDDEV_POP() , provided for compatibility with Oracle. 

If there are no matching rows, STDDEV()  returns NULL . 

This function executes as a window function if over_clause  is present. over_clause  is as described in Section 12.21.2, “Window Function Concepts and Syntax” . 

