先简单说一下我遇到的问题

我是两张表关联查询（其实是主表都全部数据，但是只保存其他表的ID），主表保存有附表的数据，但是需要将附表的数据整合到主表相同的目录下，方便前台调用。

需要的结果样式如下图1所示，但是获取到的结果总是分开的，resultMap和collection节点内容都对了好几遍，写的没问题，但是出现结果如图二所示：然后最总发现是主表的主键ID所导致的，因为主表ID每条都不一样，虽然在SQL中没查，但是编译器好像也会获取，按主键区分，所以不能直接使用原有的主键内容，组要手动设置一个，这个设置的内容是你需要划分的依据字段，如我是根据DIAGNOSIS_NO这个字段来划分数据哪些是一组的，所以用这个字段来代替主键id。

图一

{
    "code": 200,
    "msg": "成功获取",
    "data": [
        {
            "id": "",
            "nursingplanDtoList": [
                {
                    "id": "",
                    "DIAGNOSIS_NO": "38.0",
                    "FACTOR_NO": 24,
                    "DIAGNOSIS_FACTOR": "疼痛不适。"
                },
                {
                    "id": "",
                    "DIAGNOSIS_NO": "38.0",
                    "FACTOR_NO": 25,
                    "DIAGNOSIS_FACTOR": "活动无耐力。"
                },
            ],
            "PATIENT_ID": "20005369",
            "VISIT_ID": "1",
            "ADMISSION_DATE": "2020-09-22 10:20",
        }
    ]
}

图二

{
    "code": 200,
    "msg": "成功获取",
    "data": [
        {
            "id": "",
            "nursingplanDtoList": [
                {
                    "id": "",
                    "DIAGNOSIS_NO": "38.0",
                    "FACTOR_NO": 24,
                    "DIAGNOSIS_FACTOR": "疼痛不适。"
                }
            ],
            "PATIENT_ID": "20005369",
            "VISIT_ID": "1",
            "ADMISSION_DATE": "2020-09-22 10:20",
        },
        {
            "id": "",
            "nursingplanDtoList": [
                {
                    "id": "",
                    "DIAGNOSIS_NO": "38.0",
                    "FACTOR_NO": 25,
                    "DIAGNOSIS_FACTOR": "活动无耐力。"
                }
            ],
            "PATIENT_ID": "20005369",
            "VISIT_ID": "1",
            "ADMISSION_DATE": "2020-09-22 10:20",
        },
    ]
}

首先先看一下我的两张表

表一：factorDict

表二：nursingDiagnosis

Sql查询语句

        SELECT
        n.DIAGNOSIS_NO as id,
        n.PATIENT_ID,
        n.VISIT_ID,
        n.ADMISSION_DATE,
        n.DIAGNOSIS_NO,
        n.DIAGNOSIS_STATUS,
        n.DIAGNOSIS_SORT,
        n.EXPECTED_TARGET,
        n.START_DATE,
        n.STOP_DATE,
        n.FACTOR_ID as FACTOR_NO,
        n.FACTOR_STATUS,
        f.DIAGNOSIS_FACTOR
        FROM
        nursingDiagnosis n LEFT JOIN factorDcit f on n.FACTOR_ID=f.id
        WHERE
        n.PATIENT_ID = #{Patient_id}
        AND n.VISIT_ID = #{Visit_id}
        AND n.ADMISSION_DATE=#{Admission_Date}
        AND n.DIAGNOSIS_NO='38.0'
        ORDER BY
        n.DIAGNOSIS_STATUS DESC,
        n.DIAGNOSIS_SORT

总结