现在有三个表分别是:memberdata,memberexp,members他们的连接点是uid我现在不知道怎么将这三个表相连在一起:我只会如下2个相连
$SQL = "SELECT m.*, mx.* FROM members m LEFT JOIN memberexp mx USING(uid) WHERE m.uid = $uid";
请问三个如何写?
$SQL = "SELECT m.*, mx.* FROM members m LEFT JOIN memberexp mx USING(uid) WHERE m.uid = $uid";
请问三个如何写?
select m1.*,m2.*,m3.* from members m1, memberexp m2, memberdata m3
where m1.id = m2.id
and m2.id = m3.id 干嘛非要用左右连接,其实执行效率上是一样的,这样看起来还舒服