#首先执行看mysql是否开启函数 SHOW VARIABLES LIKE '%func%'; ------------------------------------------------------------------------------ #如果没有开启（OFF）则设置开启SET GLOBAL log_bin_trust_function_creators=1;------------------------------------------------------------------------------#下面是一个测试函数DELIMITER $$CREATE FUNCTION test_func(param1 VARCHAR(5),parmam2 VARCHAR(5),param3 VARCHAR(10))RETURNS TINYINTBEGIN   RETURN 1;END------------------------------------------------------------------------------#测试select test_func('aaa','bbb','ccc');------------------------------------------------------------------------------#删除函数 drop function test_func ;------------------------------------------------------------------------------#显示函数show function status------------------------------------------------------------------------------#显示函数源码show create function first_func;

 

完整的案例

DELIMITER $$CREATE FUNCTION test(x1 FLOAT,y1 FLOAT,x2 FLOAT,y2 FLOAT)RETURNS TINYINTBEGIN    IF x1 = x2 AND y1 = y2 THEN        RETURN 0;    ELSE        SET @PI = PI();        SET @a=(@x1-@x2)*@p/180;        SET @b=@p/2-@y1*@p/180;        SET @c=@p/2-@y2*@p/180;        SET @d=COS(@b)*COS(@c)+COS(@a)*SIN(@b)*SIN(@c);        SET @r = ROUND(ACOS(@d)*1000*6371.004,0);        RETURN @r;    END IF;    END