angular js variable not work

index.html

<div class="test" ng-controller="Ctrl">
    <button ng-click="removeTask(10);">remove</button>
<div>

app.js

app.controller('Ctrl', function($scope) {
    $scope.removeTask = function(taskId) {
        alert("Task Id is " + taskId);
    };
    var statement = "";
    db.transaction(function (tx) {
        //tx.executeSql('DROP TABLE IF EXISTS test_table');
        statement = "select * from objects where o.TYPES=' + taskId' GROUP BY objectid";

The alert message work perfectly, but when I try to use the variable taskId on select statement it does not work.