mysql中有关树的函数

用mysql客户端在库中建立函数queryOrgChildren（查找子节点）和queryOrgLevel（查看当前节点在树中的级别）：
DROP FUNCTION IF EXISTS `queryOrgChildren`;
CREATE  FUNCTION `queryOrgChildren`(id INT)
 RETURNS varchar(2000)
BEGIN
DECLARE tempChd VARCHAR(2000);

SET tempChd = cast(id as char);
IF tempChd is not NULL THEN
    SELECT group_concat(groupId) INTO tempChd FROM t_user_group TUG where TUG.PARENTUSERGROUPID=tempChd;
 end if;
return tempChd;
END;

DROP FUNCTION IF EXISTS `queryOrgLevel`;
CREATE  FUNCTION `queryOrgLevel`(id INT)
 RETURNS int
BEGIN

DECLARE grouplevel int;
DECLARE tempPar int;

SET grouplevel=0,tempPar=0;
SELECT PARENTUSERGroupId  INTO tempPar FROM t_user_group TUG where TUG.GROUPID=id;

WHILE tempPar != 0 DO

SET  grouplevel=grouplevel+1;

SELECT PARENTUSERGroupId INTO tempPar FROM t_user_group TUG where TUG.GROUPID=tempPar;

END WHILE;

return grouplevel;

END;

当然用户可根据上边2个函数发挥，比如写获取所有子孙节点的函数和获取所有父类节点的函数，有可能还会用到FIND_IN_SET(str,strlist)函数