计算（*）总的唯一条目，但是对于2个不同的字段(Count(*) the total unique entries but for 2 different fields)

计算（*）总的唯一条目，但是对于2个不同的字段(Count(*) the total unique entries but for 2 different fields)

我正在使用SQL Server 2005处理旧表。（该表设计得不是很好，但现在无法更改。）

我正在尝试计算2列中的唯一条目。

这给出了我需要的列表：

SELECT Name1 FROM MyTable UNION SELECT Name2 FROM MyTable -- automatically removes dups

但我怎么算这个呢？ （希望有一个声明。）像这样的东西，但语法不对：

SELECT COUNT(SELECT Name1 FROM MyTable UNION SELECT Name2 FROM MyTable)

I'm working on an old table using SQL Server 2005. (The table isn't designed very well, but it can't be changed now.)

I'm trying to count the unique entries in 2 columns.

This gives the list I need:

SELECT Name1 FROM MyTable UNION SELECT Name2 FROM MyTable -- automatically removes dups

But how would I count that? (Hopefully with 1 statement.) Something like this, but the syntax isn't right:

SELECT COUNT(SELECT Name1 FROM MyTable UNION SELECT Name2 FROM MyTable)

最满意答案

使用子查询：

SELECT COUNT（*）FROM（SELECT Name1 FROM MyTable UNION SELECT Name2 FROM MyTable）AS u

Use a subquery:

SELECT COUNT(*) FROM (SELECT Name1 FROM MyTable UNION SELECT Name2 FROM MyTable) AS u