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。