TQL – MACHBASE

TQL

It is required to properly read and transform data that has been sent by sensors. And also read and send data from database to other systems in demanded format.

Generate example ‘signal’ data

First, generate sample data for the examples below.

FAKE(
  oscillator(
    freq(15, 1.0), freq(24, 1.5),
    range('now', '10s', '1ms')
  )
)
INSERT( 'time', 'value', table('example'), tag('signal') )

Output format independent

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SQL( `SELECT TIME, VALUE FROM EXAMPLE WHERE NAME='signal' LIMIT 100` )
CSV( timeformat("Default") )

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SQL( `SELECT TIME, VALUE FROM EXAMPLE WHERE NAME='signal' LIMIT 100` )
CHART(
    size("600px", "340px"),
    chartOption({
        xAxis:{data:column(0)},
        yAxis:{},
        series:[ { type:"line", data:column(1)} ]
    })
)

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SQL(`SELECT TIME, VALUE FROM EXAMPLE WHERE NAME='signal' LIMIT 100`)
HTML({
  {{if .IsFirst }}
    <table>
    <tr>
        <th>TIME</th><th>VALUE</th>
    </tr>
  {{end}}
    <tr>
        <td>{{.V.TIME}}</td><td>{{.V.VALUE}}</td>
    </tr>
  {{if .IsLast }}
    </table>
  {{end}}
})

Data source independent

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FAKE( json({ 
    [ "A", 1.0 ],
    [ "B", 1.5 ],
    [ "C", 2.0 ],
    [ "D", 2.5 ] }))

MAPVALUE(1, value(1) * 10 )

CSV()

The purpose of TQL is transforming data format. This chapter shows how to do this without developing additional applications.

N:M transforming

Iris

The example tql code below gives a brief idea of what is TQL for.

avg. values of each classes.

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CSV(file("https://docs.machbase.com/assets/example/iris.csv"))
GROUP( by(value(4), "species"),
    avg(value(0), "Avg. Sepal L."),
    avg(value(1), "Avg. Sepal W."),
    avg(value(2), "Avg. Petal L."),
    avg(value(3), "Avg. Petal W.")
)
CHART(
    chartOption({
        "xAxis":{"type": "category", "data": column(0)},
        "yAxis": {},
        "legend": {"show": true},
        "series": [
            { "type": "bar", "name": "Avg. Sepal L.", "data": column(1)},
            { "type": "bar", "name": "Avg. Sepal W.", "data": column(2)},
            { "type": "bar", "name": "Avg. Petal L.", "data": column(3)},
            { "type": "bar", "name": "Avg. Petal W.", "data": column(4)}
        ]
    })
)

min, median, avg, max, stddev of sepal length of the setosa class.

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CSV(file("https://docs.machbase.com/assets/example/iris.csv"))
FILTER( strToUpper(value(4)) == "IRIS-SETOSA")
GROUP( by(value(4)), 
    min(value(0), "Min"),
    median(value(0), "Median"),
    avg(value(0), "Avg"),
    max(value(0), "Max"),
    stddev(value(0), "StdDev.")
)
CHART(
    chartOption({
        "xAxis": { "type": "category", "data": ["iris-setosa"]},
        "yAxis": {},
        "legend": {"show": "true"},
        "series": [
            {"type":"bar", "name": "Min", "data": column(1)},
            {"type":"bar", "name": "Median", "data": column(2)},
            {"type":"bar", "name": "Avg", "data": column(3)},
            {"type":"bar", "name": "Max", "data": column(4)},
            {"type":"bar", "name": "StdDev.", "data": column(5)}
        ]
    })
)

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CSV(file("https://docs.machbase.com/assets/example/iris.csv"))
SCRIPT({
    var board = {};
},{
    species = $.values[4];
    o = board[species];
    if(o === undefined) {
        o = {
            sepalLength: [],
            sepalWidth: [],
            petalLength: [],
            petalWidth: [],
        };
        board[species] = o;
    }
    o.sepalLength.push(parseFloat($.values[0]));
    o.sepalWidth.push(parseFloat($.values[1]));
    o.petalLength.push(parseFloat($.values[2]));
    o.petalWidth.push(parseFloat($.values[3]))
},{
    chart = {
        xAxis: {type: "category", data:[]},
        yAxis: {},
        legend: {show:true},
        series: [
            {type: "bar", name: "min. sepal L.", data:[]},
            {type: "bar", name: "max. sepal L.", data:[]},
            {type: "bar", name: "min. sepal W.", data:[]},
            {type: "bar", name: "max. sepal W.", data:[]},
            {type: "bar", name: "min. petal L.", data:[]},
            {type: "bar", name: "max. petal L.", data:[]},
            {type: "bar", name: "min. petal W.", data:[]},
            {type: "bar", name: "max. petal W.", data:[]},
        ],
    };
    for( s in board) {
        o = board[s];
        chart.xAxis.data.push(s);
        chart.series[0].data.push(Math.min(...o.sepalLength));
        chart.series[1].data.push(Math.max(...o.sepalLength));
        chart.series[2].data.push(Math.min(...o.sepalWidth));
        chart.series[3].data.push(Math.max(...o.sepalWidth));
        chart.series[4].data.push(Math.min(...o.petalLength));
        chart.series[5].data.push(Math.max(...o.petalLength));
        chart.series[6].data.push(Math.min(...o.petalWidth));
        chart.series[7].data.push(Math.max(...o.petalWidth));
    }
    $.yield(chart);
})
CHART()

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CSV(file("https://docs.machbase.com/assets/example/iris.csv"))
SCRIPT({
    var board = {};
},{
    species = $.values[4];
    o = board[species];
    if(o === undefined) {
        o = {
            sepalLength: [],
            sepalWidth: [],
            petalLength: [],
            petalWidth: [],
        };
        board[species] = o;
    }
    o.sepalLength.push(parseFloat($.values[0]));
    o.sepalWidth.push(parseFloat($.values[1]));
    o.petalLength.push(parseFloat($.values[2]));
    o.petalWidth.push(parseFloat($.values[3]))
},{
    chart = {
        title: {text: "Iris Sepal/Petal Length", left: "center"},
        grid: {bottom: "10%"},
        xAxis: {type: "category", data:[], boundaryGap: true},
        yAxis: {type: "value", splitArea:{show:true}},
        legend: {show:true, bottom:"2%"},
        tooltip: {trigger: "item", axisPointer:{type:"shadow"}},
        series: [
            {type: "boxplot", name: "sepal length", data:[]},
            {type: "boxplot", name: "petal length", data:[]},
        ],
    };
    const mx = require("mathx");
    for( s in board) {
        o = board[s];
        chart.xAxis.data.push(s);
        // sepal length
        o.sepalLength = mx.sort(o.sepalLength)
        min = Math.min(...o.sepalLength);
        max = Math.max(...o.sepalLength);
        q1 = mx.quantile(0.25, o.sepalLength);
        q2 = mx.quantile(0.5, o.sepalLength);
        q3 = mx.quantile(0.75, o.sepalLength);
        chart.series[0].data.push([min, q1, q2, q3, max]);
        // petal length
        o.petalLength = mx.sort(o.petalLength)
        min = Math.min(...o.petalLength);
        max = Math.max(...o.petalLength);
        q1 = mx.quantile(0.25, o.petalLength);
        q2 = mx.quantile(0.5, o.petalLength);
        q3 = mx.quantile(0.75, o.petalLength);
        chart.series[1].data.push([min, q1, q2, q3, max]);
    }
    $.yield(chart);
})
CHART()

In this chapter

Last updated on Mar 9, 2026