无法在CREATE FUNCTION中使用declare语句

I am trying to use a declare [variable] statement within a CREATE FUNCTION statement.

我试图在CREATE FUNCTION语句中使用declare [variable]语句。

My code is

我的代码是

/* DELIMITER // */

CREATE FUNCTION hello_world()
  RETURNS TEXT
DECLARE bae int;
BEGIN
  RETURN 'Hello World';
END;
//
/* DELIMITER ; */

The code just worked fine without using declare, but with the declare it gives me the error:

代码只是工作正常而不使用声明,但声明它给了我错误:

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use...

您的SQL语法有错误;查看与您的MySQL服务器版本对应的手册,以获得正确的语法...

How can I actually use the declare statement inside function or stored procedure?

我怎样才能在函数或存储过程中实际使用declare语句?

2 个解决方案

#1

Don't comment out the delimiter, and declares need to be immediately after the begin statement:

不要注释掉分隔符,并声明需要在begin语句之后立即:

DELIMITER // 
CREATE FUNCTION hello_world() RETURNS TEXT
BEGIN
DECLARE bae INT;
  RETURN 'Hello World';
END
//
DELIMITER; --restore delimiter

SELECT hello_world() --Hello World

EDIT:

I've never used sql fiddle. I've played with it for 5 minutes and I hate it :)

我从来没用过sql小提琴。我玩了5分钟,我讨厌它:)

Apparantly, sql fiddle has different syntax rules. The one that applies here is that they do not support delimiters, but do have // built in as a "known delimiter" (Execute triggers stored procedures on SqlFiddle. Mysql)

显然,sql小提琴有不同的语法规则。这里适用的是它们不支持分隔符,但确实//内置为“已知分隔符”(执行触发SqlFiddle上的存储过程.Mysql)

So, this works:

所以,这有效:

CREATE function hello_world() returns text
BEGIN
declare bae int;
return "hello world";
END//

select hello_world()

http://sqlfiddle.com/#!2/8e5da4/1

So, there is a working fiddle. I hand-typed the function and it works. HOWEVER, I literally copy pasted that into a new sqlfiddle and I get

所以,有一个工作小提琴。我手动输入功能,它的工作原理。但是,我真的把它粘贴到一个新的sqlfiddle中,然后我就得到了

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 3

您的SQL语法有错误;检查与MySQL服务器版本对应的手册,以便在第3行的“'附近使用正确的语法

So this inconsistant behavior is pretty annoying.

所以这种不一致的行为非常烦人。

#2

In mysql, you preface each declaration with declare, inside the begin-end block:

在mysql中,您在开始结束块内为每个声明添加了声明:

CREATE FUNCTION hello_world()
RETURNS TEXT
BEGIN
    DECLARE bae int;
    RETURN 'Hello World';
END;

#1