技術標籤：碼農之路

因為兩次都錯在這個上面上，所以還是記錄一下。。。。

resultType是直接表示返回型別的，比如Integer,String, List<Integer>也是一樣，resultMap則是對外部ResultMap的引用

例如：

  <select id="selectByStatus" resultType="java.lang.Integer" parameterType="com.meihui.learning.viewmodel.admin.question.QuestionStatusVM">
    SELECT
    t_question.id
    FROM t_question LEFT JOIN t_question_status on t_question_status.question_id = t_question.id
    <where>
      and t_question.deleted = 0
      <if test="questionType != null">
        and t_question.question_type = #{questionType}
      </if>
      <if test="wrongStatus != null ">
        and t_question_status.wrong_status= #{wrongStatus}
      </if>
      <if test="subjectSecondId != null ">
        and t_question.subject_second_id= #{subjectSecondId}
      </if>
      <if test="subjectId != null ">
        and t_question.subject_id= #{subjectId}
      </if>
    </where>
  </select>
 

  <select id="getUserDingTaskByDdUserIdDeptId" resultMap="BaseResultMap">
    select
    <include refid="Base_Column_List"/>
    from t_user_ding_task
    where dd_user_id = #{ddUserId} and dept_id = #{deptId} and deleted = 0 limit 1
  </select>

還有一種略特殊的

  <select id="selectCountByDate"  resultType="com.meihui.learning.domain.other.KeyValue">
		SELECT create_time as name,COUNT(create_time) as value from
		        (
				  SELECT DATE_FORMAT(create_time,'%Y-%m-%d') as create_time from 
                   t_user_event_log
					WHERE  create_time  between  #{startTime}  and  #{endTime}
				) a
		GROUP BY create_time
  </select>
 

    List<KeyValue> selectCountByDate(@Param("startTime") Date startTime, @Param("endTime") Date endTime);

https://blog.csdn.net/woshixuye/article/details/27521071 這位很詳細