mysql delimiter的说明

默认情况下，mysql解释器一遇到分号（;），它就要自动执行。 
不会等到用户把这些语句全部输入完之后，再执行整段语句。 

而自定义函数和存储过程的SQL语句有好多行，且语句中包含有分号，
为了保证整段语句的整体执行，就要使用delimiter，更改mysql的默认结束符。 

再看一个列子：

delimiter $$use `test`$$drop function if exists `queryOnePartnerInviteCodeByCode`$$create  function `queryOnePartnerInviteCodeByCode`(_code varchar(4000)) returns varchar(4000) charset utf8beginset _code=TRIM(_code);if _code is null or _code='' then    return null;        end if ;select GROUP_CONCAT(id) into @__userID from lcs_member where del_flag=0 and  invite_code=_code;if  @__userID is null or  @__userID='' then    return null;        end if ;select GROUP_CONCAT(id),GROUP_CONCAT(invite_code) into @__selectTmpID,@_invite_code from lcs_member where  del_flag=0 and invite_code!='' and invite_code is not null and belong_to_partner>0 and FIND_IN_SET(belong_to_partner,@__userID)>0;if (@__selectTmpID!='' and @__selectTmpID is not null ) then    return @_invite_code;else     return null;end if;    end$$delimiter ;