mysql函数可否少传参数（亲测不能够）

#测试mysql函数可否少传参数

DELIMITER //

DROP FUNCTION test//

CREATE FUNCTION test(a char(20),b char(20))

RETURNS char(20)

BEGIN

declare ret char(20);

if a is null then

set ret="null";

else

set ret="not null";

end if;

return ret;

END

//

DELIMITER ;

#返回值

mysql> select test(a="2");

1054 - Unknown column 'a' in 'field list'

mysql> select test("2");

mysql> select test("2","1");

+---------------+

| test("2","1") |

+---------------+

| not null      |

+---------------+