fix https://github.com/yulichang/mybatis-plus-join/issues/61

mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectObjs.java

@@ -27,6 +27,14 @@ public class SelectObjs extends com.baomidou.mybatisplus.core.injector.methods.S
                 copyAndSetTableName(tableInfo, getTableName(tableInfo)));
     }
 
+    @Override
+    protected String sqlSelectObjsColumns(TableInfo table) {
+        String selectColumns = super.sqlSelectObjsColumns(table);
+        return SqlScriptUtils.convertChoose(String.format("%s == null or !(%s instanceof %s)", Constants.WRAPPER, Constants.WRAPPER, MPJBaseJoin.class.getName()),
+                selectColumns, mpjSqlSelectColumns() + StringPool.SPACE + selectColumns);
+    }
+
+
     @Override
     protected String sqlWhereEntityWrapper(boolean newLine, TableInfo table) {
         return SqlScriptUtils.convertChoose(String.format("%s == null or !(%s instanceof %s)", Constants.WRAPPER, Constants.WRAPPER, MPJBaseJoin.class.getName()),

mybatis-plus-join-test/test-join/src/main/java/com/github/yulichang/test/join/entity/UserDO.java

@@ -23,7 +23,7 @@ import java.util.Map;
 @EqualsAndHashCode(callSuper = true)
 @DynamicTableName
 @FieldNameConstants
-@TableName(value = "`user`")
+@TableName(value = "`user`", autoResultMap = true)
 public class UserDO extends ID<Integer> implements Serializable {
 
     private Integer pid;

mybatis-plus-join-test/test-join/src/test/java/com/github/yulichang/test/join/LambdaWrapperTest.java

@@ -516,6 +516,19 @@ class LambdaWrapperTest {
         System.out.println(list);
     }
 
+    /**
+     * 别名测试
+     */
+    @Test
+    void testObj() {
+        ThreadLocalUtils.set("SELECT DISTINCT t1.id FROM `user` t LEFT JOIN `user` t1 ON (t1.pid = t.id) WHERE t.del=false AND t1.del=false");
+        MPJLambdaWrapper<UserDO> wrapper = new MPJLambdaWrapper<UserDO>()
+                .distinct()
+                .select(UserDO::getId)
+                .leftJoin(UserDO.class, UserDO::getPid, UserDO::getId);
+        List<Object> list = userMapper.selectObjs(wrapper);
+    }
+
     @Test
     void testTableAlias() {
         ThreadLocalUtils.set("SELECT t.id,\n" +