麻烦mySql函数

Question

我必须在mysql中创建一个返回整数的函数。 sql解释器不断告诉我，我的语法有问题。我把它看得尽可能好，并尝试了一堆东西，但我无法弄清楚。

CREATE FUNCTION no_of_paintings_exhibited (exhibition_name VARCHAR(45)) 
RETURNS INT 

BEGIN 
    DECLARE number_of_paintings INT; 

    SELECT 
    COUNT(*) 
    INTO number_of_paintings 
    FROM Exhibition, Shown_at, Painting 
    WHERE name = exhibition_name AND Painting.id_no = Shown_at.art; 

    RETURN number_of_paintings; 

END; // 

错误输出：

mysql> CREATE FUNCTION no_of_paintings_exhibited (exhibition_name VARCHAR(45)) 
-> RETURNS INT 
-> 
-> BEGIN 
->   DECLARE number_of_paintings INT; 

ERROR 1064 (42000): 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 5 

Answer 1

CREATE FUNCTION no_of_paintings_exhibited (exhibition_name VARCHAR(45)) 
RETURNS INT 

BEGIN 
    DECLARE number_of_paintings INT; 
set number_of_paintings=0; 
    SELECT 
    COUNT(*) 
    as number_of_paintings 
    FROM Exhibition ex, Shown_at shat, Painting ptng 
    WHERE ex.name = exhibition_name AND ptng.id_no = shat.art; 

    RETURN number_of_paintings; 

END; 

Answer 2

您收到此错误，因为你没有设置分隔符，默认情况下分号（;）是分隔符，一旦发现它尝试执行的第一个分号并引发此错误

执行如下操作（在创建函数之前将分隔符设置为$$或//，下面我使用$$），然后再次在函数创建后设置DELIMITER到sem我冒号。

DELIMITER $$ 
CREATE FUNCTION ... 
.. 
END; 
$$ 
DELIMITER ;