Mybatis Select Count(*)的返回值类型介绍

目录

• Select Count(*)的返回值类型
• 返回Count(*)的整数值

Select Count(*)的返回值类型

<select id=\"queryAlarmStatisticalAnalysis4System\" parameterType=\"AlarmMailSendLog\"
            resultType=\"java.lang.Integer\">
        select count(*) from mon_alarm_mail_send_log
        where is_del = \'0\'
        <if test=\"airport != null and airport != \'\'\">
            and airport = #{airport}
        </if>
        <if test=\"system != null and system != \'\'\">
            and system = #{system}
        </if>
        <if test=\"relateTable != null and relateTable != \'\'\">
            and relate_table = #{relateTable}
        </if>
        <if test=\"params.startTime != null and params.startTime != \'\'\">
            and send_time &gt;= to_date(#{params.startTime},\'yyyy-MM-dd HH24:mi:ss\')
        </if>
        <if test=\"params.endTime != null and params.endTime != \'\'\">
            and send_time &lt;= to_date(#{params.endTime},\'yyyy-MM-dd HH24:mi:ss\')
        </if>
    </select>

类似于select count(*)的语句的返回值为java.lang.Integer

返回Count(*)的整数值

1、mybatis中resultType定义为\"java.lang.Integer\"

<select id=\"selectNums\" resultType=\"java.lang.Integer\">
    select count(*) from tableName
  </select>

2、接口中返回值写成int，即可

int selectNums();

以上为个人经验，希望能给大家一个参考，也希望大家多多支持。