sys_connect_by_path函数就是从start with开始的地方开始遍历,并记下其遍历到的节点,start with开始的地方被视为根节点,将遍历到的路径根据函数中的分隔符,组成一个新的字符串。sys_connect_by_path函数用connect by来寻找下一条记录,直到迭代找不到相应记录为止。概念与递归类似,connect by指定递归(连接)条件,如...
select sys_connect_by_path(t2.ID, '/') as PATH, t1.id from HTD_DEVICETYPE_RELATION t1 inner join HTD_DEVICETYPE_RESOURCE t2 on t1.CHILD_RESOURCE_TYPE_ID = t2.ID start with t1.parent_resource_type_id = 100 and t1.id > 1 connect by nocycle prior t2.id = t1.parent_resource_ty...
insert into tab_connect_by (CHILD, PARENT) values(13, 26); insert into tab_connect_by (CHILD, PARENT) values(1, 26); insert into tab_connect_by (CHILD, PARENT) values(12, 26); insert into tab_connect_by (CHILD, PARENT) values(11, 18); insert into tab_connect_by (CHILD, PARENT...
问SYS_CONNECT_BY_PATH并以PostgreSQL等效的方式开始/连接ENPostgreSQL从小白到专家，是从入门逐渐能力提升...
PostgreSQL Oracle 兼容性之 - connect by 高级选项 CONNECT_BY_ISLEAF、SYS_CONNECT_BY_PATH、CONNECT_BY_ISCYCLE、LEVEL
create table hierarchical_functions_tb(VARCHAR2_1 VARCHAR2(100),VARCHAR2_2 VARCHAR2(100)); insert into hierarchical_functions_tb(VARCHAR2_1,VARCHAR2_2) values('hierarchical_functions_tb1','hierarchical_functions_tb2'); select sys_connect_by_path(VARCHAR2_1,'/') from hierarchical_functions_tb...
FROM (SELECT ROW_NUMBER () OVER (PARTITION BY n_sec_code ORDER BY n_sec_code, lvl DESC) rn, n_sec_code, text FROM (SELECT n_sec_code, LEVEL lvl, SYS_CONNECT_BY_PATH (c_researcher_code,'/') text FROM (SELECT n_sec_code, c_researcher_code as c_researcher_code, ...
In PostgreSQL, we can achieve a functionality similar toSYS_CONNECT_BY_PATHby concatenating the parent and child record attributes with a char/delimiter in every iteration. See the following code: WITHRECURSIVE cte(emp_no,manager_no,ename,job,level,path)AS(SELECTemp_no,manager_no,e...
sys.path.append("..") '''操作Postgresql数据库的类''' class Postgresql: '''数据库连接''' conn = None; log = None; debug = app_config.debug; util = None; def __init__(self): ''' 构建函数,...
echo deadline > /sys/block/sda/queue/scheduler 1. 注意,如果既有机械盘,又有SSD,那么可以使用/etc/rc.local,对指定磁盘修改为对应的调度策略。 关闭透明大页 # 及时生效echo'never'>/sys/kernel/mm/transparent_hugepage/defragecho'never'>/sys/kernel/mm/transparent_hugepage/enabled# 重启后自动生效echo...