单表count:

//How many robots are there?

$number = Robots::count();

echo "There are ", $number, "\n";

//How many mechanical robots are there?

$number = Robots::count("type='mechanical'");

echo "There are ", $number, " mechanical robots\n"

多表count:

$result = $this->modelsManager->createBuilder()
->columns("SysContractWarn.con_warn_id")
->from("SysCustomer")
->join("SysContract","SysCustomer.cus_id = SysContract.cus_id")
->join("SysContractWarn","SysContract.con_id = SysContractWarn.con_id")
->where($where." AND SysCustomer.serv_status = 0 AND SysContractWarn.rmk_del = 0",array("manId"=>$man->man_id))
->getQuery()
->execute()
->count();