question random update

source/xzs/src/main/resources/mapper/QuestionMapper.xml

@@ -234,12 +234,38 @@
   <select id="selectQuestionsByQuestionsNumber"
           resultMap="BaseResultMap">
     <foreach collection="eachList" item="each" separator="union">
-      (select q.skill_id, q.industry_id, i.name as industry_name, s.name as skill_name
-      , t.content ,q.difficult ,q.question_type  from t_industry i
-      join t_question q on i.id = q.industry_id
-      join t_skill s on s.id = q.skill_id
-      join t_text_content t on t.id = q.info_text_content_id
+      (SELECT
+        q.skill_id,
+        q.industry_id,
+        i. NAME AS industry_name,
+        s. NAME AS skill_name,
+        t.content,
+        q.difficult,
+        q.question_type
+      FROM
+        t_question q
+      JOIN (
+        SELECT
+          r1.id
+        FROM
+          t_question AS r1
+        JOIN (
+        SELECT
+          (
+            RAND() * (
+            SELECT
+              MAX(id)-#{each.eachNumber}
+            FROM
+              t_question
+            )
+          ) AS row_id
+        ) AS r2
+        JOIN t_industry i ON i.id = r1.industry_id
+        JOIN t_skill s ON s.id = r1.skill_id
+        JOIN t_text_content t ON t.id = r1.info_text_content_id
         <where>
+          r1.deleted=0 AND
+          r1.id >= r2.row_id
           <if test="each.difficult != null">
             and q.difficult = #{each.difficult}
           </if>
@@ -250,7 +276,13 @@
             and s.id = #{each.skillId}
           </if>
         </where>
-      limit #{each.eachNumber} )
+        ORDER BY
+        r1.id ASC
+        LIMIT #{each.eachNumber}
+      ) AS rows ON (rows.id = q.id)
+      JOIN t_industry i ON i.id = q.industry_id
+      JOIN t_skill s ON s.id = q.skill_id
+      JOIN t_text_content t ON t.id = q.info_text_content_id)
     </foreach>
 
   </select>

xzs-new.sql

@@ -374,3 +374,45 @@ CREATE TABLE `t_user_token`  (
 SET FOREIGN_KEY_CHECKS = 1;
 
 (SELECT * FROM t_question WHERE skill_id = 1 LIMIT 2) UNION (SELECT * FROM t_question WHERE skill_id = 11 LIMIT 2)  ;
+
+
+SELECT
+  q.skill_id,
+  q.industry_id,
+  i. NAME AS industry_name,
+  s. NAME AS skill_name,
+  t.content,
+  q.difficult,
+  q.question_type
+FROM
+  t_question q
+  JOIN (
+         SELECT
+           r1.id
+         FROM
+           t_question AS r1
+           JOIN (
+                  SELECT
+                    (
+                      RAND() * (
+                        SELECT
+                          MAX(id)-7
+                        FROM
+                          t_question
+                      )
+                    ) AS row_id
+                ) AS r2
+             JOIN t_industry i ON i.id = r1.industry_id
+             JOIN t_skill s ON s.id = r1.skill_id
+             JOIN t_text_content t ON t.id = r1.info_text_content_id
+         WHERE
+           r1.deleted=0 AND
+           r1.id >= r2.row_id
+           AND r1.skill_id = 10
+         ORDER BY
+           r1.id ASC
+         LIMIT 7
+       ) AS rows ON (rows.id = q.id)
+    JOIN t_industry i ON i.id = q.industry_id
+    JOIN t_skill s ON s.id = q.skill_id
+    JOIN t_text_content t ON t.id = q.info_text_content_id;