Question

我遇到了以下问题：

编写查询以查找与其他用户U完全相同的朋友。

以下是表格（和一个SQL小提琴：http://sqlfiddle.com/#!9/457260/1）：

用户：
- user_id：Int
友谊：
- user_id：Int
- friend_id：Int

我的查询问题是它返回的用户拥有相同的朋友或超过用户U.

    Function DeleteCol(iCol As Integer, strCriteria As String, strWSName As String, bPositive As Boolean)

  Dim iLastCol As Integer
  Dim wsUsed As Worksheet

  Set wsUsed = ThisWorkbook.Worksheets(strWSName)
  iLastRow = wsUsed.Cells(Rows.Count, iCol).End(xlUp).Row
  For i = iLastRow To 1 Step -1
    With wsUsed.Cells(i, iCol)
      If bPositive Then
        If .Value = strCriteria Then .EntireRow.Delete
      Else
        If .Value <> strCriteria Then .EntireRow.Delete
      End If
    End With
  Next i

End Function

Answer 1

最简单的方法是聚合朋友，然后进行比较：

with f as (
      select user_id, array_agg(friend_id order by friend_id) as friends
      from friendships f
      group by user_id
     )
select user_id
from f
where f.friends = (select friends from f where user_id = 1) and
      f.user_id <> 1;

关系部门：确切部门

1 个答案: