我有一张任务表,表里有前置任务和上级任务,试图里需要前置和上级的Code、Caption俩字段我是这么写的,应该没问题
SELECT A.*,
B.Code AS ParentCode,B.Caption AS ParentCaption,
C.Code AS FrontTaskCode,C.Caption AS FrontTaskCaption
FROM T_Project_Task AS A
LEFT JOIN T_Project_Task AS B ON A.ParentID = B.ID
LEFT JOIN T_Project_Task AS C ON A.FrontTaskID = C.ID但我觉得这么写挺低端的,LEFT JOIN都链一张表, 有没有高端些的写法呀。left join
SELECT A.*,
B.Code AS ParentCode,B.Caption AS ParentCaption,
C.Code AS FrontTaskCode,C.Caption AS FrontTaskCaption
FROM T_Project_Task AS A
LEFT JOIN T_Project_Task AS B ON A.ParentID = B.ID
LEFT JOIN T_Project_Task AS C ON A.FrontTaskID = C.ID但我觉得这么写挺低端的,LEFT JOIN都链一张表, 有没有高端些的写法呀。left join
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