Oracle start with...connect by prior 實現遞歸查詢
來源：程序員人生 發布時間：2014-12-14 08:15:51 閱讀次數：3816次
基本語法：
<span style="font-size:18px;"><em>select ... from <TableName>
where <Conditional⑴>
start with <Conditional⑵>
connect by <Conditional⑶>;
<Conditional⑴>：過濾條件，用于對返回的所有記錄進行過濾。
<Conditional⑵>：查詢結果重起始根結點的限定條件。
<Conditional⑶>：連接條件</em></span>
數據表結構以下：
create table table_test(
priorId number,
id number,
name varchar(5),
description varchar(10)
);
測試數據：
insert into table_test(priorId,id,name,description) values(0,1,'f','f父類');
insert into table_test(priorId,id,name,description) values(1,2,'f1','f子類1');
insert into table_test(priorId,id,name,description) values(1,3,'f2','f子類2');
insert into table_test(priorId,id,name,description) values(0,4,'F','F父類');
insert into table_test(priorId,id,name,description) values(4,5,'F1','F子類1');
insert into table_test(priorId,id,name,description) values(4,6,'F2','F子類2');
獲得完全樹：
select * from table_test start with priorId = 0 connect by prior id = priorId;
獲得特定子樹：
select * from table_test start with id = 1 connect by prior id = priorId;
select * from table_test start with id = 4 connect by prior id = priorId;
如果connect by prior中的prior被省略，則查詢將不進行深層遞歸：
select * from table_test start with priorId = 0 connect by id = priorId;
select * from table_test start with id = 1 connect by id = priorId;
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