Question

I am currently learning how to program in SQL. I have a table1 with firstname, lastname and roomname.
And I have another table2 that has all the roomnames.

我很想知道,如何从所有会议室的人中挑选<代码>第1号<>和>代码>。页: 1 按

Answer 1

对TransactSQL而言,如果你知道你一表中的每一行都是不同的,那么这项工作将:

SELECT
   firstname,
   lastname
FROM
   table1
GROUP BY
   firstname,
   lastname
HAVING
   COUNT(DISTINCT RoomName) = (SELECT COUNT(*) FROM table2)

如果你想要忽略某些房间,那就应该非常有效率,但不能过于灵活。

Answer 2

组合主席结果

As I can see you have duplicates in table1: Let s say:

**table1:**
firstname lastname roomname
Theodore  Hello    roomA
Mike      World    roomA
Theodore  Hello    roomB
Theodore  Hello    roomC
NickThe   Greek    roomC

And **table2:**
roomname
roomA
roomB
roomC

As you can see Theodore is the one that had passed from all rooms from table2. In common language (a good approach for constructing SQL queries) you would say: Grab the person(s) from table1 who have passed from all the rows of table2:

Take a look at here: Fetching only rows that match all entries in a joined table (SQL)

但是,正如贾梅所说,这不是一种适当的yn子和思维方式。

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