term
和 match
总结
在实际的项目查询中,term
和match
是最常用的两个查询,而经常搞不清两者有什么区别,趁机总结有空总结下。
term
用法
先看看term的定义,term是代表完全匹配,也就是精确查询,搜索前不会再对搜索词进行分词拆解。
这里通过例子来说明,先存放一些数据:
{
"title": "love China",
"content": "people very love China",
"tags": ["China", "love"]
}
{
"title": "love HuBei",
"content": "people very love HuBei",
"tags": ["HuBei", "love"]
}
来使用term
查询下:
{
"query": {
"term": {
"title": "love"
}
}
}
结果是,上面的两条数据都能查询到:
{
"took": 1,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"skipped": 0,
"failed": 0
},
"hits": {
"total": 2,
"max_score": 0.6931472,
"hits": [
{
"_index": "test",
"_type": "doc",
"_id": "8",
"_score": 0.6931472,
"_source": {
"title": "love HuBei",
"content": "people very love HuBei",
"tags": ["HuBei","love"]
}
},
{
"_index": "test",
"_type": "doc",
"_id": "7",
"_score": 0.6931472,
"_source": {
"title": "love China",
"content": "people very love China",
"tags": ["China","love"]
}
}
]
}
}
发现,title里有关love的关键字都查出来了,但是我只想精确匹配 love China
这个,按照下面的写法看看能不能查出来:
{
"query": {
"term": {
"title": "love China"
}
}
}
执行发现无数据,从概念上看,term属于精确匹配,只能查单个词。我想用term匹配多个词怎么做?可以使用terms
来:
{
"query": {
"terms": {
"title": ["love", "China"]
}
}
}
查询结果为:
{
"took": 1,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"skipped": 0,
"failed": 0
},
"hits": {
"total": 2,
"max_score": 0.6931472,
"hits": [
{
"_index": "test",
"_type": "doc",
"_id": "8",
"_score": 0.6931472,
"_source": {
"title": "love HuBei",
"content": "people very love HuBei",
"tags": ["HuBei","love"]
}
},
{
"_index": "test",
"_type": "doc",
"_id": "7",
"_score": 0.6931472,
"_source": {
"title": "love China",
"content": "people very love China",
"tags": ["China","love"]
}
}
]
}
}
发现全部查询出来,为什么?因为terms里的[ ]
多个是或者的关系,只要满足其中一个词就可以。想要通知满足两个词的话,就得使用bool的must来做,如下:
{
"query": {
"bool": {
"must": [
{
"term": {
"title": "love"
}
},
{
"term": {
"title": "china"
}
}
]
}
}
}
可以看到,我们上面使用china
是小写的。当使用的是大写的China
我们进行搜索的时候,发现搜不到任何信息。这是为什么了?title这个词在进行存储的时候,进行了分词处理。我们这里使用的是默认的分词处理器进行了分词处理。我们可以看看如何进行分词处理的?
分词处理器
GET test/_analyze
{
"text" : "love China"
}
结果为:
{
"tokens": [
{
"token": "love",
"start_offset": 0,
"end_offset": 4,
"type": "<ALPHANUM>",
"position": 0
},
{
"token": "china",
"start_offset": 5,
"end_offset": 10,
"type": "<ALPHANUM>",
"position": 1
}
]
}
分析出来的为love
和china
的两个词。而term
只能完完整整的匹配上面的词,不做任何改变的匹配。所以,我们使用China
这样的方式进行的查询的时候,就会失败。稍后会有一节专门讲解分词器。
match
用法
先用 love China
来匹配。
GET test/doc/_search
{
"query": {
"match": {
"title": "love China"
}
}
}
结果是:
{
"took": 1,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"skipped": 0,
"failed": 0
},
"hits": {
"total": 2,
"max_score": 1.3862944,
"hits": [
{
"_index": "test",
"_type": "doc",
"_id": "7",
"_score": 1.3862944,
"_source": {
"title": "love China",
"content": "people very love China",
"tags": [
"China",
"love"
]
}
},
{
"_index": "test",
"_type": "doc",
"_id": "8",
"_score": 0.6931472,
"_source": {
"title": "love HuBei",
"content": "people very love HuBei",
"tags": [
"HuBei",
"love"
]
}
}
]
}
}
发现两个都查出来了,为什么?因为match进行搜索的时候,会先进行分词拆分,拆完后,再来匹配,上面两个内容,他们title的词条为: love china hubei
,我们搜索的为love China
我们进行分词处理得到为love china
,并且属于或的关系,只要任何一个词条在里面就能匹配到。如果想 love
和 China
同时匹配到的话,怎么做?使用 match_phrase
match_phrase
用法
match_phrase
称为短语搜索,要求所有的分词必须同时出现在文档中,同时位置必须紧邻一致。
GET test/doc/_search
{
"query": {
"match_phrase": {
"title": "love china"
}
}
}
结果为:
{
"took": 5,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"skipped": 0,
"failed": 0
},
"hits": {
"total": 1,
"max_score": 1.3862944,
"hits": [
{
"_index": "test",
"_type": "doc",
"_id": "7",
"_score": 1.3862944,
"_source": {
"title": "love China",
"content": "people very love China",
"tags": [
"China",
"love"
]
}
}
]
}
}
这次好像符合我们的需求了,结果只出现了一条记录。