1.with('relation'),只预加载relation这个关联,如下面 public function relation() { return $this->hasOne(Relation::class); } 2.with(['relation', 'relation.relation1']),预加载relation以及,和relation关联的relation1 这种场景是Relation类中还定义了一个关联relation1 class Relation { public func
oracle触发器加条件判断,如果某个字段,isnode=0,那么不执行下面的方法,数据如下: create or replace trigger tr_basestation_insert_emp before insert on BJLT.BASESTATION REFERENCING NEW AS new_val OLD AS old_val --在这里设置名字,然后可引用新值,旧值 for each row ) declare --local variables here begin i
一般的,我们会在where, 或者 having中加条件,count中只是某个字段 今天看到另外一种写法,不知道性能怎么样 select count( case when xxx>10 and yyy<99 then bbb else null end) cm1, count( case when xxx>20 and yyy<1 then ccc else null end) cm2 from xxxx 基本原理是 使用了数据库count(null)时返回的是0 count(非n
thinkphp的model的where查询时有两种形式. $model->field('id')->where('customer_num is null or customer_num=""')->select(); $map['pid']=$ss; $map['type']=$s1; $list=$Region->field('id')->where($map)->select();
基础方式(自动加载) 控制器: public function ff(){ $t = new \Org\Util\Abc(); echo $t->ss(); } ThinkPHP\Library\Org\Util\Abc.class.php <?php namespace Org\Util; class Abc { public function ss(){ echo 'sss'; } } ?> 手动加载: public function ff(){ import("Org.U
问题重现 select id from big_table where name = 'sdlkfjalksdjfla' limit 100; 首先看执行计划: hive> explain select * from big_table where name = 'sdlkfjalksdjfla' limit 100; OK STAGE DEPENDENCIES: Stage-0 is a root stage STAGE PLANS: Stage: Stage-0 Fetch Oper