时间:2021-07-01 10:21:17 帮助过:5人阅读
select * from `a` ,`b` where `a`.`bid` like concat('%',`b`.`bid`,'%')
如果要查a表id等于1对应的关联数据,可以写成
select * from `a` ,`b` where `a`.`id`='1' and `a`.`bid` like concat('%',`b`.`bid`,'%')
是要查a表,结果应该类似这样:
Object{ [id] => 1 [bid] => Object { [1] => Object { id => 1 content => 'BBBBB' } [2] => Object { id => 5 content => 'BBBBB' } [3] => Object { id => 2 content => 'BBBBB' } } conent => 'AAAAA'}
类似的php伪代码应该是:
foreach ($tablea->result as $a){ echo $a->id foreach ($a->bid as $b) { echo $b.id; echo $b.content; } echo $a.conent}
你要做成这种结果,用程序很容易实现的,上面的SQL其实一定上现实了你的功能
select * from `a` ,`b` where `a`.`bid` like concat('%',`b`.`bid`,'%')
如果要查a表id等于1对应的关联数据,可以写成
select * from `a` ,`b` where `a`.`id`='1' and `a`.`bid` like concat('%',`b`.`bid`,'%')
这是是不是先读b表中的id,然后再模糊查询a表中的bid?
select * from `a` ,`b` where `a`.`bid` like concat('%',`b`.`bid`,'%')
恩,先关联AB表,然后模糊查询a表中的bid是不是在a表的bid中
这样会根据b表的id递增的顺序排序
而不是原先a表中bid逗号字符串的顺序:1,5,2??应该是1-5-2的顺序
建议贴出以下语句以便人家测试
create table ....;
insert into table.... ; 语句
select a.id, b.id as bid, a.content, b.content as bcontent from A表 a, B表 b where find_in_set(b.id, a.bid) order by a.id
select a.id, b.id as bid, a.content, b.content as bcontent from A表 a, B表 b where find_in_set(b.id, a.bid) order by a.id
你在表B加个冗余字段A_id多好。
CREATE TEMPORARY TABLE a (id int, bid varchar(10), content varchar(10));INSERT INTO a VALUES('1','1,5,2','AAAAAAA');INSERT INTO a VALUES('2','2,4','AAAAAAA');INSERT INTO a VALUES('3','1,3,2','AAAAAAA');CREATE TEMPORARY TABLE b (bid int, content varchar(10));INSERT INTO b VALUES('1','BBBBB');INSERT INTO b VALUES('2','BBBBB');INSERT INTO b VALUES('3','BBBBB');INSERT INTO b VALUES('4','BBBBB');INSERT INTO b VALUES('5','BBBBB');select a.id, b.bid as bid, a.content, b.content as bcontent from a, b where find_in_set(b.bid, a.bid) order by a.id
原来是我的“1, 5, 2”逗号后面有空格!就没法全查询出来了!空格去掉就ok了
另外,这个find_in_set的查询结果没法按照1-5-2的原始顺序排列!只能按1-2-5递增或5-2-1递减的次序排列啊?
唠叨老大用了另一种更有效率的写法,不过我那些其实也可以得出一样的结果的!
select * from `a` ,`b` where `a`.`bid` like concat('%',`b`.`bid`,'%') order by id