假设我有一个如下所示的数组：
var data = [{
"categories": [{
"categoryName": "belt",
"categoryValue": "white"
}, {"categoryName": "level", "categoryValue": "Beginner"}, {
"categoryName": "type",
"categoryValue": "technique"
}], "id": 1, "skillName": "Beginner 1", "skips": 0, "weight": 1
}, {
"categories": [{"categoryName": "belt", "categoryValue": "white"}, {
"categoryName": "level",
"categoryValue": "Beginner"
}, {"categoryName": "type", "categoryValue": "technique"}],
"id": 2,
"skillName": "Beginner 2",
"skips": 0,
"weight": 1
}, {
"categories": [{"categoryName": "belt", "categoryValue": "white"}, {
"categoryName": "level",
"categoryValue": "Beginner"
}, {"categoryName": "type", "categoryValue": "technique"}],
"id": 3,
"skillName": "Beginner 3",
"skips": 0,
"weight": 1
}, {
"categories": [{"categoryName": "belt", "categoryValue": "white"}, {
"categoryName": "level",
"categoryValue": "Beginner"
}, {"categoryName": "type", "categoryValue": "technique"}],
"id": 4,
"skillName": "Beginner 4",
"skips": 0,
"weight": 1
}, {
"categories": [{"categoryName": "belt", "categoryValue": "white"}, {
"categoryName": "level",
"categoryValue": "Beginner"
}, {"categoryName": "type", "categoryValue": "technique"}],
"id": 5,
"skillName": "Beginner 5",
"skips": 0,
"weight": 1
},
...
{
"categories": [{"categoryName": "belt", "categoryValue": "orange"}, {
"categoryName": "level",
"categoryValue": "Intermediate"
}, {"categoryName": "type", "categoryValue": "technique"}],
"id": 13,
"skillName": "Intermediate 3",
"skips": 0,
"weight": 1
}, {
"categories": [{"categoryName": "belt", "categoryValue": "orange"}, {
"categoryName": "level",
"categoryValue": "Intermediate"
}, {"categoryName": "type", "categoryValue": "technique"}],
"id": 14,
"skillName": "Intermediate 4",
"skips": 0,
"weight": 1
}, {
"categories": [{"categoryName": "belt", "categoryValue": "orange"}, {
"categoryName": "level",
"categoryValue": "Intermediate"
}, {"categoryName": "type", "categoryValue": "technique"}],
"id": 15,
"skillName": "Intermediate 5",
"skips": 0,
"weight": 1
}, {
"categories": [{"categoryName": "belt", "categoryValue": "purple"}, {
"categoryName": "level",
"categoryValue": "Intermediate"
}, {"categoryName": "type", "categoryValue": "technique"}],
"id": 16,
"skillName": "Intermediate 6",
"skips": 0,
"weight": 1
}
...
]
我们想要查询一下，例如：
alasql('SEARCH /categories/categoryValue WHERE(categoryName="belt") FROM ?', [data]);
这可能会给你一些类似的东西：
['white', 'white', 'white',...'orange', 'orange',...'purple'...]
我想要的是：
['white', 'orange', 'purple']
有没有办法在查询方面执行此操作，或者在返回后是否需要将其过滤为唯一值？