min by (projectId)(avg_over_time(cpu_util{tenantId="49858159166402560"}[300s] offset 5m))
统计方式：
avg_over_time，max_over_time，min_over_time，sum_over_time
汇聚函数：
avg by，sum by，max by，min by
prometheus过滤必须包含某个维度的指标
lbaas_listener_id=~".+"
无数据表达式
absent_over_time(mysql_performance_com_insert[10m] offset 1m)
(avg_over_time(used_memory_rss{dcs_cluster_proxy_node!~".+",dcs_cluster_redis_node=~"ec651e8355aae325dc6663919be84ac8",dcs_instance_id=~".+",projectId=~"49858159166402560",tenantId=~"49858159166402560"}[5m]
offset 5m)) > 0
(absent_over_time(Connum{InstanceId=~"lb-j4gze6b0|lb-otku5r2k",loadBalancerPort!~".+",projectId=~"80766653910319104",protocol!~".+",tenantId=~"80766653910319104",vip=~"81.71.82.85|172.16.0.9",vpcId!~".+"}[5m] offset 5m)) == 1