[Solved]-How to show first and last label of x axis Highcharts-Highcharts

Ahh I used tickPositioner and solved it!

xAxis: {
    type: 'Linear',
    tickmarkPlacement: 'on',
    tickPositioner: function() {
        var positions = [],
            ext = this.getExtremes(),
            xMax = Math.round(ext.max),
            xMin = Math.round(ext.min);

        for (var i = xMin; i < xMax; i++) {
            if (i % <?php echo number_format($num_results/3,0);?> == 0) {
                positions.push(i);
            }
        }
        positions.push(xMax);
        return positions;
    },
    labels: {
        autoRotation: 0,
    },
    categories:  ["2017-07","2017-08","2017-09","2017-10","2017-11","2017-12","2018-01","2018-02","2018-03","2018-04","2018-05","2018-06","2018-07","2018-08","2018-09","2018-10","2018-11","2018-12","2019-01","2019-02","2019-03","2019-04","2019-05","2019-06"]
}