thinkphp 3.2 unionall

$where['enterprise_id'] = $enterpriseId;
//企业名称不为空
if(!empty($enterpriseName)){
$where['enterprise_name'] = array('like',"%$enterpriseName%");

}
$table2 = array('enterprise_data.yunkh_enterprise_rel_enterprise'=>'ed_ere',
'enterprise_data.yunkh_enterprise_info'=>'ed_ei');
$where2 = array('ed_ere.enterprise_id'=>$enterpriseId,
'status'=>'1',
'ed_ei.enterprise_name'=>array('like',"%$enterpriseName%"),
'_string'=>'ed_ere.rel_enterprise_id = ed_ei.enterprise_id');
$contractInfoList =
$this->model->field('enterprise_id,enterprise_name')
->table(array('enterprise_data.yunkh_enterprise_info' => 'ed_id'))
->where($where)
->union(array('field'=>'ed_ei.enterprise_id,enterprise_name','table'=>$table2,'where'=>$where2),true)
->select();
return $contractInfoList;

执行的sql：
SELECT 'enterprise_id','enterprise_name'
FROM enterprise_data.yunkh_enterprise_info 'ed_id' WHERE 'enterprise_id' = 1 AND 'enterprise_name' LIKE '%农%'
UNION ALL
SELECT ed_ei.enterprise_id,'enterprise_name'
FROM enterprise_data.yunkh_enterprise_rel_enterprise 'ed_ere',enterprise_data.yunkh_enterprise_info 'ed_ei'
WHERE ed_ere.enterprise_id = 1 AND 'status' = '1' AND ed_ei.enterprise_name LIKE '%农%'
AND ( ed_ere.rel_enterprise_id = ed_ei.enterprise_id )