我有三张桌子，其中两张桌子结构相同
像这样的表1
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id title description image
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1 title1 desc1 image1.png
2 title2 desc2 image2.jpg
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这样的表2
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id title description image
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1 ttl1 des1 img1.png
2 ttl2 des2 img2.jpg
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表3就像这样
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id table1_id table2_id
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1 0 1
2 1 0
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我想将table3连接到id不为零的其他表之一。
答案 0 :(得分：1)
select * from table3 t3
join table1 t1 on t1.id = t3.table2_id
join table2 t2 on t2.id = t3.table1_id
Where t3.table2_id <> 0 or t3.table1_id <> 0
直接join与Where
答案 1 :(得分：0)
(select * from table3 as t3 join table1 as t1 on t1.id = t3.id and t3.table1_id != 0)
UNION
(select * from table3 as t3 join table2 as t2 on t2.id = t3.id and t3.table2_id != 0)