这是我参与8月更文挑战的第24天，活动详情查看：8月更文挑战
本Elasticsearch相关文章的版本为：7.4.2
范围查询: 获取数值型、日期型和字符串型字段的特定范围的文档，对数字范围进行过滤尤其是在数据分析时会更有用。例如：获取价格大于20小于30的商品数据：
SQL：
select good from goods where price>20 and price<30;
那么，在Elasticsearch中，实现上面的范围查询是使用range查询, 支持的关系运算符有：
| 运算符 | 说明 |
|---|---|
| gt | 大于(great than的首字母缩写) |
| lt | 小于(less than的首字母缩写) |
| gte | 大于等于(great than or equal的首字母缩写) |
| lte | 小于等于(less than or equal的首字母缩写) |
数值型范围查询
构造点测试数据：
POST /num_range_test_index/_doc/1
{
"price": 10
}
POST /num_range_test_index/_doc/2
{
"price": 20
}
POST /num_range_test_index/_doc/3
{
"price": 30
}
POST /num_range_test_index/_doc/4
{
"price": 22
}
POST /num_range_test_index/_doc/5
{
"price": 15
}
所以上述的例子获取价格大于20小于30的商品数据在Elasticsearch中是这样查询的：
GET /num_range_test_index/_search
{
"query": {
"constant_score": {
"filter": {
"range": {
"price": {
"gte": 20,
"lte": 30
}
}
}
}
}
}
返回的结果：
{
"took" : 225,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 3,
"relation" : "eq"
},
"max_score" : 1.0,
"hits" : [
{
"_index" : "num_range_test_index",
"_type" : "_doc",
"_id" : "2",
"_score" : 1.0,
"_source" : {
"price" : 20
}
},
{
"_index" : "num_range_test_index",
"_type" : "_doc",
"_id" : "3",
"_score" : 1.0,
"_source" : {
"price" : 30
}
},
{
"_index" : "num_range_test_index",
"_type" : "_doc",
"_id" : "4",
"_score" : 1.0,
"_source" : {
"price" : 22
}
}
]
}
}
日期型范围查询
构造点测试数据：
POST /date_range_test_index/_doc/1
{
"market_at": "2021-07-01"
}
POST /date_range_test_index/_doc/2
{
"market_at": "2021-08-01"
}
POST /date_range_test_index/_doc/3
{
"market_at": "2021-08-22"
}
获取上市日期大于2021-08-01且小于2021-08-24的商品数据在Elasticsearch中是这样查询的：
GET /date_range_test_index/_search
{
"query": {
"constant_score": {
"filter": {
"range": {
"market_at": {
"gt": "2021-08-01",
"lt": "2021-08-24"
}
}
}
}
}
}
返回的结果：
{
"took" : 0,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 1,
"relation" : "eq"
},
"max_score" : 1.0,
"hits" : [
{
"_index" : "date_range_test_index",
"_type" : "_doc",
"_id" : "3",
"_score" : 1.0,
"_source" : {
"market_at" : "2021-08-22"
}
}
]
}
}
字符串型范围查询
字符串的范围查询是按照字符序进行排序的。例如'a'<'b'。 构造点测试数据：
POST /string_range_test_index/_doc/1
{
"goods_name": "apple"
}
POST /string_range_test_index/_doc/2
{
"goods_name": "banana"
}
POST /string_range_test_index/_doc/3
{
"goods_name": "orange"
}
获取商品名大于小于的商品数据在Elasticsearch中是这样查询的：
GET /string_range_test_index/_search
{
"query": {
"constant_score": {
"filter": {
"range": {
"goods_name": {
"gte": "a",
"lt": "c"
}
}
}
}
}
}
返回的结果：
{
"took" : 0,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 2,
"relation" : "eq"
},
"max_score" : 1.0,
"hits" : [
{
"_index" : "string_range_test_index",
"_type" : "_doc",
"_id" : "1",
"_score" : 1.0,
"_source" : {
"goods_name" : "apple"
}
},
{
"_index" : "string_range_test_index",
"_type" : "_doc",
"_id" : "2",
"_score" : 1.0,
"_source" : {
"goods_name" : "banana"
}
}
]
}
}
