依靠连接表 [英] Count on a table with joins

问题描述

我想在一个表的列上执行计数功能，在该列上我还执行了与其他表的多次联接.
我面临的问题是，计数是在完全联接的结果上执行的，在我的情况下，我希望在特定的表上执行计数.我应该如何解决这个问题? /div>

只需在查询中返回其他值.
从性能的角度来看，我认为这不是最好的方法，但是它应该可以工作.

选择*，(从tab1中选择count(*))，从tab1，tab2，tab3中，其中tab1.a = tab2.a和.......

您可以完全使用单独的选择语句.

I want to perform a count function on a column of a table where i have also performed multiples joins with other tables.
The problem i''m facing is that the count was performed on the result of the complete joins where in my case i want it to performed on that particular table.How should i solved this

解决方案

Just return additional values in your query.
I dont think this is the best way from a performance perspective, but it should work.

select *, (select count(*) from tab1) from tab1, tab2, tab3 where tab1.a = tab2.a and.......

You could use a completely separate select statement for it.

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