From 51e1db2bc42e3c0cb793bc640eaff1888456fdd8 Mon Sep 17 00:00:00 2001
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 <8605635+zhang3064194730@user.noreply.gitee.com>
Date: Mon, 30 Dec 2024 20:58:05 +0800
Subject: [PATCH] =?UTF-8?q?refactor:=20=E6=9B=B4=E6=94=B9=E5=AD=90?=
 =?UTF-8?q?=E6=9F=A5=E8=AF=A2=E4=B8=BAjoin?=
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---
 .../mapper/course/CourseCollectDao.xml        | 144 ++++++++++--------
 1 file changed, 80 insertions(+), 64 deletions(-)

diff --git a/src/main/resources/mapper/course/CourseCollectDao.xml b/src/main/resources/mapper/course/CourseCollectDao.xml
index d60f4a9a..3bd35678 100644
--- a/src/main/resources/mapper/course/CourseCollectDao.xml
+++ b/src/main/resources/mapper/course/CourseCollectDao.xml
@@ -6,75 +6,91 @@
 
     <select id="selectCourseByCollect" resultType="com.sqx.modules.course.entity.Course">
         SELECT
-            MAX(u.update_time) AS produceEndTime,
-            c.*,
-            d1.course_details_name AS courseDetailsName,
-            d1.course_details_id AS courseDetailsId,
-            COUNT(d2.course_details_id) AS courseDetailsCount
+        MAX(u.update_time) AS produceEndTime,
+        c.*,
+        d.course_details_name AS courseDetailsName,
+        d.course_details_id AS courseDetailsId,
+        cd.course_details_count AS courseDetailsCount
         FROM
-            course_collect u
-                LEFT JOIN
-            course c ON u.course_id = c.course_id
-                LEFT JOIN
-            course_collect cc1 ON cc1.course_id = u.course_id
-                AND cc1.classify = 3
-                AND cc1.user_id = #{userId}
-                LEFT JOIN
-            course_details d1 ON cc1.course_details_id = d1.course_details_id
-                LEFT JOIN
-            course_details d2 ON d2.course_id = c.course_id
+        course_collect u
+        LEFT JOIN course c ON u.course_id = c.course_id
+        LEFT JOIN (
+        SELECT
+        cc.course_id,
+        cc.user_id,
+        d.course_details_name,
+        d.course_details_id
+        FROM
+        course_collect cc
+        LEFT JOIN course_details d ON cc.course_details_id = d.course_details_id
         WHERE
-            u.user_id = #{userId}
-          AND c.course_id IS NOT NULL
-          AND u.classify = #{classify}
-        GROUP BY
-            u.course_id, c.course_id
+        cc.classify = 3
+        AND cc.user_id = #{userId}
         ORDER BY
-            produceEndTime DESC;
+        cc.update_time DESC
+        ) AS d ON u.course_id = d.course_id
+        LEFT JOIN (
+        SELECT
+        d.course_id,
+        COUNT(*) AS course_details_count
+        FROM
+        course_details d
+        GROUP BY
+        d.course_id
+        ) AS cd ON c.course_id = cd.course_id
+        WHERE
+        u.user_id = #{userId}
+        AND c.course_id IS NOT NULL
+        AND u.classify = #{classify}
+        GROUP BY
+        u.course_id
+        ORDER BY
+        produceEndTime DESC
 
 
- <!--       SELECT
-            MAX( u.update_time ) AS produceEndTime,
-            c.*,
-            (
-                SELECT
-                    d.course_details_name
-                FROM
-                    course_collect cc
-                        LEFT JOIN course_details d ON cc.course_details_id = d.course_details_id
-                WHERE
-                    d.course_id = u.course_id
-                  AND cc.classify = 3 and cc.user_id=#{userId}
-                ORDER BY
-                    cc.update_time DESC
-                                    LIMIT 1
-            ) AS courseDetailsName,
-	(
-	SELECT
-		d.course_details_id
-	FROM
-		course_collect cc
-		LEFT JOIN course_details d ON cc.course_details_id = d.course_details_id
-	WHERE
-		d.course_id = u.course_id
-		AND cc.classify = 3 and cc.user_id=#{userId}
-	ORDER BY
-		cc.update_time DESC
-		LIMIT 1
-	) AS courseDetailsId,
-	( SELECT count(*) FROM course_details d WHERE d.course_id = c.course_id ) AS courseDetailsCount
-        FROM
-            course_collect u
-            LEFT JOIN course c ON u.course_id = c.course_id
-        WHERE
-            u.user_id = #{userId}
-          AND c.course_id IS NOT NULL
-          AND u.classify = #{classify}
-        GROUP BY
-            u.course_id
-        ORDER BY
-            produceEndTime DESC
-            -->
+
+        <!--       SELECT
+                   MAX( u.update_time ) AS produceEndTime,
+                   c.*,
+                   (
+                       SELECT
+                           d.course_details_name
+                       FROM
+                           course_collect cc
+                               LEFT JOIN course_details d ON cc.course_details_id = d.course_details_id
+                       WHERE
+                           d.course_id = u.course_id
+                         AND cc.classify = 3 and cc.user_id=#{userId}
+                       ORDER BY
+                           cc.update_time DESC
+                                           LIMIT 1
+                   ) AS courseDetailsName,
+           (
+           SELECT
+               d.course_details_id
+           FROM
+               course_collect cc
+               LEFT JOIN course_details d ON cc.course_details_id = d.course_details_id
+           WHERE
+               d.course_id = u.course_id
+               AND cc.classify = 3 and cc.user_id=#{userId}
+           ORDER BY
+               cc.update_time DESC
+               LIMIT 1
+           ) AS courseDetailsId,
+           ( SELECT count(*) FROM course_details d WHERE d.course_id = c.course_id ) AS courseDetailsCount
+               FROM
+                   course_collect u
+                   LEFT JOIN course c ON u.course_id = c.course_id
+               WHERE
+                   u.user_id = #{userId}
+                 AND c.course_id IS NOT NULL
+                 AND u.classify = #{classify}
+               GROUP BY
+                   u.course_id
+               ORDER BY
+                   produceEndTime DESC
+                   -->
     </select>
 
 </mapper>