SQL同时查询父子名称的SQL查询语句的写法ID ParentID Name ParentName

示例：parentid是1就是id为1的公司的子公司

解法：

SELECT sub.orgName AS 公司名, main.orgName AS 父公司名FROM 表名 main JOIN 表名 sub ON (main.id = sub.parentId)

 

在开发中近常会遇到这样的查询（如果是JDBC方式或者纯SQL语句查询的话）：

如果一个表里面存在id和parentId，你又想同时查询出name和parentName既可以使用下面的方式查询哦。

select child.NAME,child.ID,child.PARENT_ID,parent.name as PARENT_NAME FROM tb_dictionary parent left join tb_dictionary child on parent.id=child.parent_id 

 

SELECT
    DISTINCT 
    Prt_AlarmRecord.PartCode 
    ,Bmt_Part.PartNameFull  FROM [Prt_AlarmRecord] 
    LEFT JOIN
   (SELECT
    child.[GUID],child.[ParentGUID],child.PartCode  AS PartCode,
    CASE WHEN
    parent.[PartName]
    IS NULL
    THEN 
    child.[PartName]
    ELSE
    (CAST(isnull(parent.[PartName],'')  as varchar(100))) +'|'+(CAST(child.[PartName] as varchar(100)))
    END
    AS PartNameFull

    FROM Bmt_Part child  LEFT JOIN Bmt_Part parent on parent.[GUID]=child.[ParentGUID]
    )
    AS  Bmt_Part  ON  [Prt_AlarmRecord].PartCode =Bmt_Part.PartCode 
    
WHERE [StartTime] >='2020-04-21 17:56:09' AND [EndTime]<= '2020-04-21 17:56:09'
ORDER BY PartNameFull ASC