ECharts と golang 実践ガイド: 多様な統計グラフの作成に関するチュートリアル

import (
    "database/sql"
    "fmt"
    _ "github.com/go-sql-driver/mysql"
)

func main() {
    // connect to database server
    db, err := sql.Open("mysql", "user:password@tcp(127.0.0.1:3306)/database_name")
    if err != nil {
        fmt.Println("Failed to connect to database: ", err)
        return
    }
    defer db.Close()

    // execute query
    rows, err := db.Query("SELECT * FROM table_name")
    if err != nil {
        fmt.Println("Failed to execute query: ", err)
        return
    }
    defer rows.Close()

    // process query result
    for rows.Next() {
        var field1 int
        var field2 string
        // read fields from row
        err = rows.Scan(&field1, &field2)
        if err != nil {
            fmt.Println("Failed to read row: ", err)
            continue
        }
        // do something with fields
        fmt.Println(field1, field2)
    }
}

import (
    "github.com/chenjiandongx/go-echarts/charts"
    "github.com/chenjiandongx/go-echarts/opts"
)

func main() {
    // create a bar chart
    bar := charts.NewBar()

    // set chart title and axes labels
    bar.SetGlobalOptions(
        charts.WithTitleOpts(opts.Title{
            Title: "Bar Chart Example",
        }),
        charts.WithXAxisOpts(opts.XAxis{
            Name: "X Axis",
        }),
        charts.WithYAxisOpts(opts.YAxis{
            Name: "Y Axis",
        }),
    )

    // add data series to chart
    bar.AddSeries("Series 1", []opts.BarData{
        {Name: "A", Value: 10},
        {Name: "B", Value: 20},
        {Name: "C", Value: 30},
        {Name: "D", Value: 40},
        {Name: "E", Value: 50},
    })

    // render chart to HTML page
    page := charts.NewPage()
    page.Add(bar)
    page.Render("bar.html")
}

import (
    "database/sql"
    "fmt"
    _ "github.com/go-sql-driver/mysql"
    "github.com/gin-gonic/gin"
    "github.com/pkg/errors"
    "net/http"
)

func main() {
    r := gin.Default()
    r.LoadHTMLGlob("templates/*")

    // define route handler
    r.GET("/bar/:table/:x/:y", func(c *gin.Context) {
        table := c.Param("table")
        x := c.Param("x")
        y := c.Param("y")
        data, err := queryData(table, x, y)
        if err != nil {
            c.String(http.StatusInternalServerError, "Failed to query data: "+err.Error())
            return
        }
        bar := charts.NewBar()
        bar.SetGlobalOptions(
            charts.WithTitleOpts(opts.Title{
                Title: fmt.Sprintf("Bar Chart (%s vs %s)", x, y),
            }),
            charts.WithXAxisOpts(opts.XAxis{
                Name: x,
            }),
            charts.WithYAxisOpts(opts.YAxis{
                Name: y,
            }),
        )
        bar.AddSeries(table, data)
        c.HTML(http.StatusOK, "bar.html", gin.H{
            "graph": bar.JSChart(),
        })
    })

    // listen on port 8080
    r.Run(":8080")
}

// query data from MySQL database
func queryData(table, x, y string) ([]opts.BarData, error) {
    db, err := sql.Open("mysql", "user:password@tcp(127.0.0.1:3306)/database_name")
    if err != nil {
        return nil, errors.Wrap(err, "Failed to connect to database")
    }
    defer db.Close()
    rows, err := db.Query(fmt.Sprintf("SELECT %s, %s FROM %s", x, y, table))
    if err != nil {
        return nil, errors.Wrap(err, "Failed to execute query")
    }
    defer rows.Close()
    var result []opts.BarData
    for rows.Next() {
        var field1 string
        var field2 float64
        err = rows.Scan(&field1, &field2)
        if err != nil {
            return nil, errors.Wrap(err, "Failed to read row")
        }
        result = append(result, opts.BarData{Name: field1, Value: field2})
    }
    return result, nil
}