mybatis 查询集合里每一条数据包含子查询结果集。一对多查询，一对一查询，子查询。

实现方案：子查询

我重新写了一个实体类来作为返回给前端

public class LanguageVO {
    private String code;
    private String zhLanguage;    //中文
    private String cnLanguage;    //英文
    private List<TLanguageIta> list;   //其它语言

get  set方法略.....

}

原实体类：

public class LanguageI {
    private String id;

private String code;
    
    private String languageType;

private String content;

get  set方法略..

}

方案一： 直接在类中用注解方式实现：

@Select("select code from language  group by code")
    @Results({
         @Result(property = "code", column = "code"),
         @Result(property = "list", column = "code",
             many  =@Many(select ="com.mapper.TLanguageItaMapper.getLanguageListByCode")),
         @Result(property = "zhLanguage", column = "code",
              one =@One(select ="com.mapper.TLanguageItaMapper.getZhLanguage")),
         @Result(property = "cnLanguage", column = "code",
               one =@One(select ="com.mapper.TLanguageItaMapper.getCnLanguage"))
         })
    List<LanguageVO> getLanguageListByPage();

@Select("select t.id,t.code,t.language_type as languageType,"
            + "t.content,t.remark from language t where t.code = #{code}")
    List<TLanguageIta> getLanguageListByCode(@Param("code")String code);
    @Select("select t.content from language t where t.code = #{code} and t.language_type = '1'")
    String getZhLanguage(@Param("code")String code);
    @Select("select t.content from language t where t.code = #{code} and t.language_type = '2'")
      String getCnLanguage(@Param("code")String code);

方案二：在xml中实现

<resultMap type="com.vo.TLanguageVO" id="getLanguageList">
       <result column="code" property="code"/>
       <association property="zhLanguage"
                     select="getZhLanguage"
                     column="code"/>
     <association property="cnLanguage"
                     select="getCnLanguage"
                     column="code"/>
     <collection property="list"
                    select="getLanguageListByCode"
                    column="code"/>           
  </resultMap>
  <select id="getLanguageListByPage" resultMap="getLanguageList" >

<select id="getZhLanguage" resultType="String">
      select t.content from language t where t.code = #{code} and t.language_type = '1'
  </select>
    <select id="getCnLanguage" resultType="String">
      select t.content from language t where t.code = #{code} and t.language_type = '2'
  </select>
  <select id="getLanguageListByCode" resultMap="BaseResultMap">
      select t.id,t.code,t.language_type,t.content,t.remark from  language t 
      where t.code = #{code}
  </select>