Aggregate Function Descriptions 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 . 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. 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 . 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 . 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. 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” . 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” . 2403 • STDDEV( expr ) [ over_clause ] • STD( expr ) [ over_clause ] mysql>  SELECT student_name, MIN(test_score), MAX(test_score) FROM student GROUP BY student_name; mysql>  SELECT student_name, MIN(test_score), MAX(test_score) FROM student GROUP BY student_name; • MIN([DISTINCT]  expr ) [ over_clause ] If there are no matching rows,  MIN()  returns  NULL .