【sql】關聯查詢+表自關聯查詢

表：

經銷商 dealer   字段 uid  parent_uid  name  

聯系人 contact  字段 uid  dealer_id  contact_main

 

需求：

想要查詢到經銷商的信息，和本經銷商的主要聯系人的信息 ，和本經銷商的父級經銷商的name

 

情況：

可能有parent_id是null

 

sql語句：

    SELECT
        dea.uid uid,
        dea.enabled_flag enabledFlag,
        dea.delete_flag deleteFlag,
        dea.tenement_id tenementId,
        dea.parent_id parentId,
        pd.name parentName,
        dea.name name,
        dea.type type,
        dea.bar_code barCode,
        dea.outer_code outerCode,
        dea.outer_id outerId,
        dea.mne_code  mneCode,
        dea.address address,
        dea.address_xy addressXy,
        dea.business_area businessArea,
        dea.business_area_xy businessAreaXy,
        con.name  contactName,
        con.mobile mobile
    FROM
        dealer AS dea
    LEFT JOIN  (select * from contact where tenement_id = '9f63f84f-52c6-4c8e-b3c3-66b9f1f283ba' and main_contact = 1) con ON dea.uid = con.dealer_id

    LEFT JOIN  dealer pd on pd.uid = dea.parent_id