尝试以下操作以获得明智的结果：
SELECt gender, COUNT(User_id) AS countFROM UserGROUP BY gender;
输出：
| gender | count ||--------|-------|| F | 4 || M | 2 |
尝试以下操作以获得总计的行明智结果：
SELECt (IFNull(gender,'Total')) AS gender,COUNT(User_id) AS CountFROM UserGROUP BY genderWITH rollup;
输出：
| gender | Count ||--------|-------|| F | 4 || M | 2 || Total | 6 |
尝试此操作以获得列明智的结果：
SELECt COUNT(CASE WHEN gender = 'M' THEN User_id END) AS males, COUNT(CASE WHEN gender = 'F' THEN User_id END) AS females, COUNT(*) AS TotalFROM User;
输出：
| males | females | Total ||-------|---------|-------|| 2 | 4 | 6 |
