我有一个更新查询，如下所示 -
udate table1 tbl_out
set column1 =
(select colValue from table1 t1, table2 t2
where table1.product_id = table2.product_id
and t1.id = tbl_out.id)
where tbl_out.column1 is null;
这很有效。但是有些列的table1.product_id值为null。
因此，对于这些记录where table1.product_id = table2.product_id条件不满足且记录未更新。
我尝试按以下方式添加此条件 -
where (table1.product_id = table2.product_id OR table1.product_id is null)
and t1.id = tbl_out.id
但是这将返回多于1行，并且上面的update语句将失败。 我知道在这种情况下出现了一些可能非常简单的问题，但可能并不清楚。
Ca有人帮我这个吗？
答案 0 :(得分：0)
udate table1 tbl_out
set column1 =
(select colValue from table1 t1, table2 t2
where nvl(table1.product_id,table2.product_id) = table2.product_id
and t1.id = tbl_out.id)
where tbl_out.column1 is null;
答案 1 :(得分：0)
我认为您正在寻找一个简单的相关子查询，这意味着您不需要子查询中的<div class="container">
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quis, sem. Nulla consequat massa quis enim.</p>
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vulputate eleifend tellus.</p>
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Curabitur ullamcorper ultricies nisi.</p>
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Donec vitae sapien ut libero venenatis faucibus. Nullam quis ante. Etiam sit amet orci eget eros faucibus tincidunt. Duis leo. Sed fringilla mauris sit amet nibh. Donec sodales sagittis magna. Sed consequat, leo eget bibendum sodales, augue velit
cursus nunc,</p>
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<p>Yeah</p>
</div>
</div>：
JOIN您可能还需要update table1 tbl_out
set column1 = (select t2.colValue
from table2 t2
where t2.product_id = tbl_out.product_id
)
where tbl_out.column1 is null;
子句：
exists编辑：
如果update table1 tbl_out
set column1 = (select t2.colValue
from table2 t2
where t2.product_id = tbl_out.product_id
)
where tbl_out.column1 is null and
exists (select 1
from table2 t2
where t2.product_id = tbl_out.product_id
);
中的值为NULL，并且您尝试将其视为有效密钥：
table2