如题所述
第1个回答 2022-05-17
用DISTINCT和 均可,查count,等于1说明只有一个值。
如表名是user,字段是name:
1.根据DISTINCT函数:SELECT count(DISTINCT name) FROM user;
2.根据 GROUP BY分组:SELECT count(name) FROM user GROUP BY name;
如表名是user,字段是name:
1.根据DISTINCT函数:SELECT count(DISTINCT name) FROM user;
2.根据 GROUP BY分组:SELECT count(name) FROM user GROUP BY name;