mysql 分组后 每组随机取一条记录 求sql语句答:CREATE TABLE test_gd2gd2(id INT,type INT,str CHAR(3));INSERT INTO test_gd2gd2 SELECT 1, 0, 'aaa' UNION ALL SELECT 2, 0, 'bbb' UNION ALL SELECT 3, 1, 'sss' UNION ALL SELECT 4, 1, 'ddd' UNION ALL SELECT 5, 2, 'ggg' UNION ALL SELECT 6,...