UES (427,34,'COUNT DISTINCT','Syntax:\nCOUNT(DISTINCT expr,[expr...])\n\nReturns a count of the number of rows with different non-NULL expr\nvalues.\n\nIf there are no matching rows, COUNT(DISTINCT) returns 0.\n\nURL: https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html\n\n','mysql> SELECT COUNT(DISTINCT results) FROM student;\n','https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html');