如何在 SQL 查询中使用 SQL 函数
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How do I use a SQL function inside my SQL query
提问by Vivian River
Suppose that I have a SQL function called MAGICthat returns the magical value of a number.
假设我有一个调用的 SQL 函数MAGIC，它返回一个数字的神奇值。
Suppose further that I want to write a SQL query that will return a list of numbers from a SQL table along with their magical values.
进一步假设我想编写一个 SQL 查询，该查询将从 SQL 表中返回一个数字列表及其神奇的值。
My instinct is to write
我的直觉是写作
SELECT number, MAGIC(number) FROM NUMBERS;
However, this returns the error message `MAGIC is not a recognized function name. How can I make this work?
但是，这会返回错误消息“MAGIC 不是可识别的函数名称”。我怎样才能使这项工作？
EDIT: It looks like MAGIC is set up to be a table-valued function even though it returns only a single value. My DBA will not give me access to any database function code, so I have to work with it that way.
编辑：看起来 MAGIC 被设置为一个表值函数，即使它只返回一个值。我的 DBA 不会让我访问任何数据库函数代码，所以我必须以这种方式使用它。
回答by C-Pound Guru
If it is a scalar-value function, fully qualify your function in the TSQL:
如果它是标量值函数，请在 TSQL 中完全限定您的函数：
SELECT number, dbo.MAGIC(number) FROM NUMBERS;
回答by prilldev
If its a table-valued function, then just do this:
如果它是一个表值函数，那么只需执行以下操作：
SELECT n.number, mn.number FROM numbers as n CROSS JOIN dbo.Magic(n.number) as mn
回答by hector teran
Try using the function like a field... this is for TSQL.
尝试使用像字段一样的函数...这是用于 TSQL。
SELECT number,
-- start function
(SELECT function_field_name FROM dbo.MAGIC(number)) AS magic_number
-- end function
FROM dbo.NUMBERS
