SQL Server 2000 中的这个操作数（*= 星号等于）是什么？

发布于 2024-11-14 08:13:17 字数 468 浏览 3 评论 0原文

我有一个从 ms sql 2000 中提取并插入到 MySql 查询中的查询。它不起作用，MySql 会因 *= 运算符而卡住。在此示例中，我有两个名为 person_name 的 varchar 列。

SELECT * FROM tbl1 a, tbl2 b 
WHERE a.id = b.id
AND a.person_name *= b.person_name

我知道在其他语言中 myInt *= myTotal 也可以读作 myInt * myInt = myTotal。但是，我正在使用包含所有字符但不包含整数的 varchar。我这样写：

AND a.person_name * a.person_name = b.person_name

瞧！看来这已经奏效了。有人可以解释发生了什么事吗？ *= 运算符是将字符转换为其整数等效项还是？为什么我在网络上找不到这个运营商？

原文

I have a query that I pulled from ms sql 2000 and plugged into a MySql query. It did not work, MySql would choke on the *= operator. In this example I have two varchar columns called person_name.

SELECT * FROM tbl1 a, tbl2 b 
WHERE a.id = b.id
AND a.person_name *= b.person_name

I know in other languages myInt *= myTotal could also be read as myInt * myInt = myTotal. However, I'm working with varchars that contain all chars, no integers. I wrote it out like:

AND a.person_name * a.person_name = b.person_name

Voila! It appears to have worked. Can somebody explain what is happening? Is the *= operator converting the chars to their integer equivalents or? And why couldn't I find this operator anywhere on the web?

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不语却知心 2024-11-21 08:13:17

在 SQL 2000 中，这被用作 LEFT OUTER JOIN

=* 是 RIGHT OUTER JOIN

您的查询可以是：

SELECT 
  * 
FROM 
  tbl1 a LEFT OUTER JOIN tbl2 b ON a.person_name = b.person_name
WHERE 
  a.id = b.id

如所述此处：

使用以下方式指定外连接
非标准产品特定语法
和 WHERE 子句。 *= 运算符
用于指定左外连接
=* 运算符用于指定
右外连接。

In SQL 2000 this was used as a LEFT OUTER JOIN

=* is a RIGHT OUTER JOIN

Your query could be:

SELECT 
  * 
FROM 
  tbl1 a LEFT OUTER JOIN tbl2 b ON a.person_name = b.person_name
WHERE 
  a.id = b.id

As stated here:

Specifies an outer join using the
nonstandard product-specific syntax
and the WHERE clause. The *= operator
is used to specify a left outer join
and the =* operator is used to specify
a right outer join.

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