refactor: 更改子查询为join

src/main/resources/mapper/course/CourseDao.xml

@@ -7,6 +7,111 @@
         where course_id = #{id}
     </update>
     <select id="selectCourse" resultType="Map">
+        SELECT
+        c.classify_id AS classifyId,
+        c.course_id AS courseId,
+        c.course_label AS courseLabel,
+        c.create_time AS createTime,
+        c.details,
+        c.img,
+        c.banner_img AS bannerImg,
+        c.status,
+        c.is_delete AS isDelete,
+        c.msg_type AS msgType,
+        c.msg_url AS msgUrl,
+        c.pay_num AS payNum,
+        c.price,
+        c.wholesale_price AS wholesalePrice,
+        c.is_over AS isOver,
+        c.title,
+        c.is_price AS isPrice,
+        c.title_img AS titleImg,
+        c.update_time AS updateTime,
+        cc.classification_name AS classificationName,
+        c.course_type AS courseType,
+        c.banner_id AS bannerId,
+        b.name AS bannerName,
+        0 AS viewCounts,
+        c.dy_img_id AS dyImgId,
+        c.dy_course_id AS dyCourseId,
+        c.wx_course_id AS wxCourseId,
+        c.wx_show AS wxShow,
+        c.dy_show AS dyShow,
+        c.sort,
+        ROUND(10000 * RAND(), 0) AS goodNum,
+        d.courseDetailsCount,
+        NULL AS courseDetailsName,
+        NULL AS courseDetailsId,
+        ROUND(10000 * RAND(), 0) AS weekGoodNum,
+        0 AS isRecommend
+        FROM
+        course AS c
+        LEFT JOIN
+        course_classification AS cc ON c.classify_id = cc.classification_id
+        LEFT JOIN
+        banner AS b ON b.id = c.banner_id
+        LEFT JOIN
+        (SELECT course_id, COUNT(*) AS courseDetailsCount
+        FROM course_details
+        GROUP BY course_id) AS d ON c.course_id = d.course_id
+        LEFT JOIN
+        (SELECT course_id FROM course_details WHERE good = 1) AS gd ON c.course_id = gd.course_id
+        WHERE
+        c.is_delete = 0
+        <if test='null != wxShow and wxShow == 1'>
+            AND c.wx_show = #{wxShow}
+        </if>
+        <if test='null != wxShow and wxShow == 2'>
+            AND (c.wx_show = #{wxShow} OR c.wx_show IS NULL)
+        </if>
+        <if test='null != dyShow and dyShow == 1'>
+            AND c.dy_show = #{dyShow}
+        </if>
+        <if test='null != dyShow and dyShow == 2'>
+            AND (c.dy_show = #{dyShow} OR c.dy_show IS NULL)
+        </if>
+        <if test='null != title'>
+            AND c.title LIKE CONCAT('%', #{title}, '%')
+        </if>
+        <if test='null != classifyId and classifyId != 0'>
+            AND c.classify_id = #{classifyId}
+        </if>
+        <if test='null != bannerId and bannerId != 0'>
+            AND c.banner_id = #{bannerId}
+        </if>
+        <if test="classifyId == 0">
+            AND c.is_recommend = 1
+        </if>
+        <if test="over != null">
+            AND c.is_over = #{over}
+        </if>
+        <if test="isRecommend != null and isRecommend != -1">
+            AND gd.course_id IS NOT NULL
+        </if>
+        <if test="status != null and status != 0">
+            AND c.status = #{status}
+        </if>
+        <if test="isPrice != null">
+            AND c.is_price = #{isPrice}
+        </if>
+        <if test="wxCourse != null">
+            AND c.wx_course_id IS NOT NULL
+        </if>
+        <if test="dyCourse != null">
+            AND c.dy_status = 4
+        </if>
+        <if test="sort == null">
+            ORDER BY c.sort ASC, c.create_time DESC
+        </if>
+        <if test="sort != null and sort == 1">
+            ORDER BY goodNum DESC
+        </if>
+        <if test="sort != null and sort == 2">
+            ORDER BY weekGoodNum DESC
+        </if>;
+
+
+<!--
         SELECT
         c.classify_id as classifyId,
         c.course_id as courseId,
@@ -102,6 +207,7 @@
         <if test="sort!=null and sort==2">
             order by weekGoodNum desc
         </if>
+        -->
     </select>
 
     <select id="selectCourseAdmin" resultType="Map">