SQL检查列中的所有值 | SQL检查列中的所有值

本文介绍了SQL检查列中的所有值的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我在Oracle DB中有下表.

I have the following table in Oracle DB.

ID  VALUE
-----------
1   1
1   2
1   3
2   1
2   2
3   1
3   2
3   3
4   1

如何选择具有所有3个值(1,2,3)的ID

How can I select ID's which have all 3 values (1,2,3)

推荐答案

最简单的选项通常是这样的

The simplest option is generally something like this

SQL> ed
Wrote file afiedt.buf

  1  with x as (
  2    select 1 id, 1 val from dual union all
  3    select 1 id, 2 val from dual union all
  4    select 1 id, 3 val from dual union all
  5    select 2 id, 1 val from dual union all
  6    select 2 id, 2 val from dual union all
  7    select 3 id, 1 val from dual union all
  8    select 3 id, 2 val from dual union all
  9    select 3 id, 3 val from dual union all
 10    select 4 id, 1 val from dual
 11  )
 12  select id
 13    from x
 14   where val in (1,2,3)
 15   group by id
 16* having count(distinct val) = 3
SQL> /

        ID
----------
         1
         3

WHERE子句标识您感兴趣的值.HAVING子句告诉您其中需要存在多少个这些值.例如，如果您希望所有具有至少3个值中的2个的行，则可以更改HAVING子句以查找2的COUNT.

The WHERE clause identifies the values you're interested in. The HAVING clause tells you how many of those values need to exist. If you wanted all the rows that had at least 2 of the 3 values, for example, you'd change the HAVING clause to look for a COUNT of 2.

如果保证每个id特定的val最多出现一次，则可以在HAVING子句中消除distinct.

If a particular val is guaranteed to occur at most once per id, you can eliminate the distinct in the HAVING clause.

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