Go

在进行查询之前，需要先构造 QueryRequest 对象，然后通过以下语言查询 GreptimeDB 中的数据：

  • SQL
  • PromQL (TODO)
  • RangePromQL

例如使用 SQL 查询：

go

  1. func Query() {
  2.     // Query with metric via Sql, you can do it via PromQL
  3.     queryRequest := greptime.QueryRequest{}
  4.     // if you want to specify another database, you can specify it via: `WithDatabase(database)`
  5.     queryRequest.WithSql("SELECT * FROM monitor") // .WithDatabase(database)
  7.     resMetric, err := client.Query(context.Background(), queryRequest)
  8.     if err != nil {
  9.         fmt.Printf("fail to query, err: %+v\n", err)
  10.         return
  11.     }
  13.     type Monitor struct {
  14.         host   string
  15.         cpu    float64
  16.         memory int64
  17.         ts     time.Time
  18.     }
  20.     monitors := []Monitor{}
  21.     for _, series := range resMetric.GetSeries() {
  22.         monitor := Monitor{}
  23.         host, exist := series.Get("host") // you can directly call Get and do the type assertion
  24.         if exist {
  25.             monitor.host = host.(string)
  26.         }
  27.         monitor.cpu, _ = series.GetFloat("cpu")     // also, you can directly GetFloat
  28.         monitor.memory, _ = series.GetInt("memory") // also, you can directly GetInt
  29.         monitor.ts = series.GetTimestamp()          // GetTimestamp
  30.         monitors = append(monitors, monitor)
  31.     }
  32.     fmt.Println(monitors)
  33. }