Question

怎样用sql语句在一张表里创建含有父级id的表

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Answer 1

create table t2( itemid int,itemname varchar(20),parentid int,remark varchar(20)) insert into t2 (itemid ,itemname ,parentid ) values (1,'a',0);insert into t2 (itemid ,itemname ,parentid ) values (2,'b',1);insert into t2 (itemid ,itemname ,parentid ) values (3,'c',1);insert into t2 (itemid ,itemname ,parentid ) values (4,'d',1);insert into t2 (itemid ,itemname ,parentid ) values (5,'e',1); select a.* ,b.itemname from (select * from t2 where itemid != 1) a left join (select * from t2 where itemid =1) bon a.parentid =b.itemid