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elasticsearch查询opendistrosql支持的操作

原创 zayki 2022-11-10
1088

基本操作

要使用该功能,需要将请求发送到_opendistro/_sqlURI。您可以使用请求参数或请求正文(推荐)。

GET https://<host>:<port>/_opendistro/_sql?sql=select * from my-index limit 50
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POST https://<host>:<port>/_opendistro/_sql
{
  "query": "SELECT * FROM my-index LIMIT 50"
}
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您还可以使用curl命令:

curl -XPOST https://localhost:9200/_opendistro/_sql -u username:password -k -d '{"query": "SELECT * FROM kibana_sample_data_flights LIMIT 10"}' -H 'Content-Type: application/json'
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默认情况下,查询返回JSON,但您也可以选择CSV格式返回数据,需要对format参数进行设置:

POST _opendistro/_sql?format=csv
{
  "query": "SELECT * FROM my-index LIMIT 50"
}
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CSV格式返回数据时,每行对应一个文档,每列对应一个字段。

支持操作

我们支持的SQL操作包括声明、条件、聚合函数、Include和Exclude、常用函数、连接join和展示等操作。

  • 声明statements

    Statement Example
    Select SELECT * FROM my-index
    Delete DELETE FROM my-index WHERE _id=1
    Where SELECT * FROM my-index WHERE [‘field’]=‘value’
    Order by SELECT * FROM my-index ORDER BY _id asc
    Group by SELECT * FROM my-index GROUP BY range(age, 20,30,39)
    Limit SELECT * FROM my-index LIMIT 50 (default is 200)
    Union SELECT * FROM my-index1 UNION SELECT * FROM my-index2
    Minus SELECT * FROM my-index1 MINUS SELECT * FROM my-index2

    说明:

    与任何复杂查询一样,大型UNION和MINUS语句可能会使集群资源紧张甚至崩溃。

  • 条件Conditions

    Condition Example
    Like SELECT * FROM my-index WHERE name LIKE ‘j%’
    And SELECT * FROM my-index WHERE name LIKE ‘j%’ AND age > 21
    Or SELECT * FROM my-index WHERE name LIKE ‘j%’ OR age > 21
    Count distinct SELECT count(distinct age) FROM my-index
    In SELECT * FROM my-index WHERE name IN (‘alejandro’, ‘carolina’)
    Not SELECT * FROM my-index WHERE name NOT IN (‘jane’)
    Between SELECT * FROM my-index WHERE age BETWEEN 20 AND 30
    Aliases SELECT avg(age) AS Average_Age FROM my-index
    Date SELECT * FROM my-index WHERE birthday=‘1990-11-15’
    Null SELECT * FROM my-index WHERE name IS NULL
  • 聚合函数Aggregation

    Aggregation Example
    avg() SELECT avg(age) FROM my-index
    count() SELECT count(age) FROM my-index
    max() SELECT max(age) AS Highest_Age FROM my-index
    min() SELECT min(age) AS Lowest_Age FROM my-index
    sum() SELECT sum(age) AS Age_Sum FROM my-index
  • Include和Exclude字段

    Pattern Example
    include() SELECT include(‘a*’), exclude(‘age’) FROM my-index
    exclude() SELECT exclude(’*name’) FROM my-index
  • 函数Functions

    Function Example
    floor SELECT floor(number) AS Rounded_Down FROM my-index
    trim SELECT trim(name) FROM my-index
    log SELECT log(number) FROM my-index
    log10 SELECT log10(number) FROM my-index
    substring SELECT substring(name, 2,5) FROM my-index
    round SELECT round(number) FROM my-index
    sqrt SELECT sqrt(number) FROM my-index
    concat_ws SELECT concat_ws(’ ', age, height) AS combined FROM my-index
    / SELECT number / 100 FROM my-index
    % SELECT number % 100 FROM my-index
    date_format SELECT date_format(date, ‘Y’) FROM my-index说明:

    必须在文档映射中启用fielddata才能使大多数字符串函数正常工作。

  • 连接操作Joins

    Join Example
    Inner join SELECT p.firstname, p.lastname, p.gender, dogs.name FROM people p JOIN dogs d ON d.holdersName = p.firstname WHERE p.age > 12 AND d.age > 1
    Left outer join SELECT p.firstname, p.lastname, p.gender, dogs.name FROM people p LEFT JOIN dogs d ON d.holdersName = p.firstname
    Cross join SELECT p.firstname, p.lastname, p.gender, dogs.name FROM people p CROSS JOIN dogs d

    相关约束和限制,参考“连接操作Joins”

  • 展示Show

    展示show操作与索引模式匹配的索引和映射。您可以使用*或%使用通配符。

    Show Example
    Show tables like SHOW TABLES LIKE logs-*

连接操作Joins

Open Distro for Elasticsearch SQL支持inner joins, left outer joins,和cross joins。Join操作有许多约束:

  • 您只能加入两个参数。

  • 您必须为索引使用别名(例如people p)。

  • 在ON子句中,您只能使用AND条件。

  • 在WHERE语句中,不要将包含多个索引的树组合在一起。例如,以下语句有效:

    WHERE (a.type1 > 3 OR a.type1 < 0) AND (b.type2 > 4 OR b.type2 < -1)
    
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    以下声明无效:

    WHERE (a.type1 > 3 OR b.type2 < 0) AND (a.type1 > 4 OR b.type2 < -1)
    
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