delete t from (select c_cardno from tb_card where c_num =1)

以下是C语言猜数字游戏的代码：

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

int main()
{
    int secret_num, guess_num;
    srand(time(NULL));
    secret_num = rand() % 10 + 1; //生成1-10的随机数
    do {
        printf("Enter your guess number(1-10): ");
        scanf("%d", &guess_num);
        if (guess_num == secret_num) {
            printf("You are amazing, you got it!\n");
            break;
        } else if (guess_num > secret_num) {
            printf("Too big! Guess again.\n");
        } else {
            printf("Too small! Guess again.\n");
        }
    } while (1);
    return 0;
}

如果您需要更多关于C语言猜数字游戏的代码实现，您可以访问CSDN网站获取更多实例。

相关问题

select employee_number, card_number FROM ( SELECT id, employee_number, card_number FROM ( SELECT case when LENGTH(pin) = 5 THEN CONCAT('000', pin) ELSE pin end as employee_number, cardno as card_number, '' AS id from gate_staff union ALL SELECT employee_number, card_number, id FROM gate_mdm_dm_cardinfo WHERE id in ( SELECT max(id) as maxId FROM gate_mdm_dm_cardinfo a INNER JOIN ( SELECT employee_number, MAX(last_update_time) max_date FROM gate_mdm_dm_cardinfo WHERE last_update_time <![CDATA[ >= ]]> #{startTime} AND last_update_time <![CDATA[ <= ]]> #{endTime} GROUP BY employee_number ) b ON a.employee_number = b.employee_number AND a.last_update_time = b.max_date GROUP BY a.employee_number) and status = 1 and public_flag = 'Y' ) as mid group by employee_number, card_number having count(*) = 1 ) AS ccc WHERE ccc.id != ''; 优化这段代码

可以尝试对这段代码进行优化的几个方面：

1. 使用JOIN替代子查询：将gate_mdm_dm_cardinfo表中的子查询替换为JOIN操作，可以提高查询性能。将子查询中的条件移至ON子句中，以减少结果集大小。

SELECT employee_number, card_number
FROM (
    SELECT id, employee_number, card_number
    FROM (
        SELECT CASE
                WHEN LENGTH(pin) = 5 THEN CONCAT('000', pin)
                ELSE pin
            END AS employee_number,
            cardno AS card_number,
            '' AS id
        FROM gate_staff
        UNION ALL
        SELECT employee_number, card_number, id
        FROM gate_mdm_dm_cardinfo a
        INNER JOIN (
            SELECT employee_number, MAX(last_update_time) max_date
            FROM gate_mdm_dm_cardinfo
            WHERE last_update_time >= #{startTime} AND last_update_time <= #{endTime}
            GROUP BY employee_number
        ) b ON a.employee_number = b.employee_number AND a.last_update_time = b.max_date
        WHERE a.status = 1 AND a.public_flag = 'Y'
    ) AS mid
    GROUP BY employee_number, card_number
    HAVING COUNT(*) = 1
) AS ccc
WHERE ccc.id != '';

2. 添加索引：根据查询中涉及的字段，在gate_staff表和gate_mdm_dm_cardinfo表上添加适当的索引，以加快查询速度。

3. 优化查询计划：使用数据库的查询优化工具，如EXPLAIN语句，来分析查询计划并进行优化。根据分析结果，可以考虑调整查询的顺序、添加或删除索引等操作。

请注意，实际优化效果可能因数据库的特性和数据量而有所不同。建议在进行任何更改之前先备份数据库，并在测试环境中进行验证。

前端传来的搜索条件 1. pageNum: 1 2. pageSize: 20 3. schoolId: 12 4. clockTime_begin: 2023-08-02 5. clockTime_end: 2023-08-03 ``` <select id="selectAttStudentRecordList" parameterType="AttStudentRecord" resultMap="AttStudentRecordResult"> <include refid="selectAttStudentRecordVo"/> <where> <if test="schoolId != null "> and school_id = #{schoolId}</if> <if test="parentId != null "> and parent_id = #{parentId}</if> <if test="studentId != null "> and student_id = #{studentId}</if> <if test="stuName != null and stuName != ''"> and stu_name like concat('%', #{stuName}, '%')</if> <if test="stuNo != null and stuNo != ''"> and stu_no = #{stuNo}</if> <if test="cardNo != null and cardNo != ''"> and card_no = #{cardNo}</if> <if test="clockType != null "> and clock_type = #{clockType}</if> <if test="imgUrl != null and imgUrl != ''"> and img_url = #{imgUrl}</if> <if test="clock_time != null" > and clock_time =#{clockTime}</if> <if test="channelName != null and channelName != ''"> and channel_name like concat('%', #{channelName}, '%')</if> <if test="deviceId != null "> and device_id = #{deviceId}</if> <if test="tenantId != null "> and tenant_id = #{tenantId}</if> and del_flag = 0 </where> </select> 我在xml文件中的where要怎么写

你可以根据前端传来的搜索条件，在XML文件的`<where>`标签中编写相应的条件语句。以下是根据你提供的搜索条件示例的XML代码示例：

<select id="selectAttStudentRecordList" parameterType="AttStudentRecord" resultMap="AttStudentRecordResult">
    <include refid="selectAttStudentRecordVo" />
    <where>
        <if test="schoolId != null ">and school_id = #{schoolId}</if>
        <if test="clockTime_begin != null ">and clock_time &gt;= #{clockTime_begin}</if>
        <if test="clockTime_end != null ">and clock_time &lt;= #{clockTime_end}</if>
        and del_flag = 0
    </where>
</select>

以上示例中，根据前端传来的搜索条件，我仅添加了`schoolId`和`clockTime`的判断条件。你可以根据需要添加其他条件，如`pageNum`、`pageSize`等。

请注意，示例中使用了`&gt;=`和`&lt;=`来表示大于等于和小于等于的比较操作符，这是因为XML文件中需要使用实体编码来表示特殊字符。

希望这能帮到你！如果有任何进一步的问题，请随时问我。