两张表由外键相联 要查第一张表中 除第二张表有的外键之外的所有数据 应该怎么写？
------解决思路----------------------
select a.*,b.col1,b.col2,.....
from a
left join b on a.bid=b.id
或者
select a.*,b.col1,b.col2,.....
from a
inner join b on a.bid=b.id
------解决思路----------------------
SELECT *
FROM t1
WHERE NOT EXISTS(
SELECT *
FROM t2
WHERE t2.fk = t1.id
)