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db/Elasticsearch系列/9-11文档操作/5-Elasticsearch之分页查询

2020-03-10

5-Elasticsearch之分页查询

一 准备数据

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PUT lqz/doc/1
{
"name":"顾老二",
"age":30,
"from": "gu",
"desc": "皮肤黑、武器长、性格直",
"tags": ["黑", "长", "直"]
}

PUT lqz/doc/2
{
"name":"大娘子",
"age":18,
"from":"sheng",
"desc":"肤白貌美,娇憨可爱",
"tags":["白", "富","美"]
}

PUT lqz/doc/3
{
"name":"龙套偏房",
"age":22,
"from":"gu",
"desc":"mmp,没怎么看,不知道怎么形容",
"tags":["造数据", "真","难"]
}


PUT lqz/doc/4
{
"name":"石头",
"age":29,
"from":"gu",
"desc":"粗中有细,狐假虎威",
"tags":["粗", "大","猛"]
}

PUT lqz/doc/5
{
"name":"魏行首",
"age":25,
"from":"广云台",
"desc":"仿佛兮若轻云之蔽月,飘飘兮若流风之回雪,mmp,最后竟然没有嫁给顾老二!",
"tags":["闭月","羞花"]
}

二 分页查询:from/size

我们来看看elasticsearch是怎么将结果分页的:

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GET lqz/doc/_search
{
"query": {
"match_all": {}
},
"sort": [
{
"age": {
"order": "desc"
}
}
],
"from": 2,
"size": 1
}

上例,首先以age降序排序,查询所有。并且在查询的时候,添加两个属性fromsize来控制查询结果集的数据条数。

  • from:从哪开始查
  • size:返回几条结果

如上例的结果:

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{
"took" : 0,
"timed_out" : false,
"_shards" : {
"total" : 5,
"successful" : 5,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : 5,
"max_score" : null,
"hits" : [
{
"_index" : "lqz",
"_type" : "doc",
"_id" : "5",
"_score" : null,
"_source" : {
"name" : "魏行首",
"age" : 25,
"from" : "广云台",
"desc" : "仿佛兮若轻云之蔽月,飘飘兮若流风之回雪,mmp,最后竟然没有嫁给顾老二!",
"tags" : [
"闭月",
"羞花"
]
},
"sort" : [
25
]
}
]
}
}

上例中,在返回的结果集中,从第2条开始,返回1条数据。

那如果想要从第2条开始,返回2条结果怎么做呢?

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GET lqz/doc/_search
{
"query": {
"match_all": {}
},
"sort": [
{
"age": {
"order": "desc"
}
}
],
"from": 2,
"size": 2
}

上例中,我们指定from为2,意为从第2条开始返回,返回多少呢?size意为2条。

还可以这样:

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GET lqz/doc/_search
{
"query": {
"match_all": {}
},
"sort": [
{
"age": {
"order": "desc"
}
}
],
"from": 4,
"size": 2
}

上例中,从第4条开始返回2条数据。

结果如下:

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{
"took" : 0,
"timed_out" : false,
"_shards" : {
"total" : 5,
"successful" : 5,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : 5,
"max_score" : null,
"hits" : [
{
"_index" : "lqz",
"_type" : "doc",
"_id" : "2",
"_score" : null,
"_source" : {
"name" : "大娘子",
"age" : 18,
"from" : "sheng",
"desc" : "肤白貌美,娇憨可爱",
"tags" : [
"白",
"富",
"美"
]
},
"sort" : [
18
]
}
]
}
}

上例中仅有一条数据,那是为啥呢?因为我们现在只有5条数据,从第4条开始查询,就只有1条符合条件,所以,就返回了1条数据。

学到这里,我们也可以看到,我们的查询条件越来越多,开始仅是简单查询,慢慢增加条件查询,增加排序,对返回结果进行限制。所以,我们可以说:对于elasticsearch来说,所有的条件都是可插拔的,彼此之间用,分割。比如说,我们在查询中,仅对返回结果进行限制:

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GET lqz/doc/_search
{
"query": {
"match_all": {}
},
"from": 4,
"size": 2
}

上例中,在所有的返回结果中,结果从4开始返回2条数据。

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{
"took" : 0,
"timed_out" : false,
"_shards" : {
"total" : 5,
"successful" : 5,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : 5,
"max_score" : 1.0,
"hits" : [
{
"_index" : "lqz",
"_type" : "doc",
"_id" : "3",
"_score" : 1.0,
"_source" : {
"name" : "龙套偏房",
"age" : 22,
"from" : "gu",
"desc" : "mmp,没怎么看,不知道怎么形容",
"tags" : [
"造数据",
"真",
"难"
]
}
}
]
}
}

但我们只有1条符合条件的数据。

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