fix:Fix: 修复含特殊 ORDER BY 的查询生成总数 SQL 时的语法错误

--在 isSimpleCount 方法中新增对 ORDER BY 条件的判断逻辑，当查询包含含占位符的 CASE WHEN 排序、布尔排序等特殊 ORDER BY 子句时，不再误判为 "简单查询"，避免生成包含ORDER BY的COUNT(0)错误SQL，解决聚合查询中ORDER BY字段未参与GROUP BY的语法报错问题。

Author: 彭卫东

src/main/java/com/github/pagehelper/parser/defaults/DefaultCountSqlParser.java

@@ -162,6 +162,10 @@ public Select sqlToCount(Select select, String name) {
      * @return
      */
     public boolean isSimpleCount(PlainSelect select) {
+        //包含order by的时候不可以
+        if (select.getOrderByElements() != null) {
+            return false;
+        }
         //包含group by的时候不可以
         if (select.getGroupBy() != null) {
             return false;

src/test/java/com/github/pagehelper/mapper/UserMapper.java

@@ -135,4 +135,8 @@ public interface UserMapper {
     List<Map<String, Object>> execute(@Param("sql") String sql);
 
     List<UserCode> selectByCode(Code code);
+
+    List<User> selectOrderByBool(@Param("py") String py);
+
+    List<User> selectOrderByCase(@Param("py") String py);
 }

src/test/java/com/github/pagehelper/test/basic/count/TestOrderBy.java

@@ -0,0 +1,44 @@
+package com.github.pagehelper.test.basic.count;
+
+import com.github.pagehelper.Page;
+import com.github.pagehelper.PageHelper;
+import com.github.pagehelper.mapper.UserMapper;
+import com.github.pagehelper.model.User;
+import com.github.pagehelper.util.MybatisHelper;
+import org.apache.ibatis.session.SqlSession;
+import org.junit.Test;
+
+/**
+ * @author light pwd
+ * @description
+ * @date 2025/10/22
+ */
+public class TestOrderBy {
+
+    @Test
+    public void testOrderByBool() throws ClassNotFoundException {
+        Class.forName("org.postgresql.Driver");
+        SqlSession sqlSession = MybatisHelper.getSqlSession();
+        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
+        try {
+            Page<User> page = PageHelper.startPage(1, 10);
+            userMapper.selectOrderByBool("ZSJ");
+        } finally {
+            sqlSession.close();
+        }
+    }
+
+
+    @Test
+    public void testOrderByCase() throws ClassNotFoundException {
+        Class.forName("org.postgresql.Driver");
+        SqlSession sqlSession = MybatisHelper.getSqlSession();
+        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
+        try {
+            Page<User> page = PageHelper.startPage(1, 10);
+            userMapper.selectOrderByCase("CNZ");
+        } finally {
+            sqlSession.close();
+        }
+    }
+}

src/test/resources/com/github/pagehelper/mapper/UserMapper.xml

@@ -569,4 +569,17 @@
         left join salaries s on e.emp_no = s.emp_no
         order by e.emp_no, s.from_date
     </select>
+
+    <select id="selectOrderByBool" resultType="com.github.pagehelper.model.User">
+        select *
+        from public."user"
+        order by py = #{py} desc nulls last
+    </select>
+
+    <select id="selectOrderByCase" resultType="com.github.pagehelper.model.User">
+        select *
+        from public."user"
+        order by CASE WHEN py = #{py} THEN 0 ELSE 1 END,
+            py DESC NULLS LAST
+    </select>
 </mapper>