我无法绘制 JSON_ARRAYAGG function .
mybatisMap器：

<mapper namespace="com.test.mapper.UserEntityMapper">
    <resultMap id="userMap" type="UserVO">
        <id property="id" column="id" />
        <result property="username" column="username"/>
        <collection property="pictures" ofType="PictureVO">
            <id property="id" column="id" />
            <result property="location" column="location" />
        </collection>
    </resultMap>
    <select id="findUserById" parameterType="map" resultMap="userMap">
        SELECT
        users.id,
        users.username,
        JSON_ARRAYAGG(
            JSON_OBJECT(
                "id",
                pic.id,
                "location",
                pic.location
            ) 
        ) AS pictures
        FROM
            users
            LEFT JOIN pictures pic ON users.id = pic.user_id 
        WHERE
            users.id = 1
    </select>
</mapper>

用户VO模型：

@Getter
@Setter
@NoArgsConstructor
public class UserVO {
    private Long id;
    private String username;
    private List<PictureVO> pictures;
}

picturevo型号：

@Getter
@Setter
@NoArgsConstructor
public class PictureVO {
    private Long id;
    private String location;
}

调用api的结果：

{
    "id": 1,
    "username": "connor",
    "pictures": [
        {
            "id": 1,
            "location": null
        }
    ]
}

如你所见 pictures 只有一个 id 可以正确Map。假设有两个结果 pictures ，如果我直接执行sql，这里只返回1。