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最新文章列表
用elasticsearch聚合函数实现distinct查询
1.等价的sql
SELECT DISTINCT field1,field2 FROM test_index.test_type
等价于
SELECT field1,field2 FROM test_index.test_type GROUP BY field1,field2
2.而group by的查询,在es中我们可以用Aggregation(聚合)去实现,等价的DSL查询语 ...
关于graphite聚合aggregator的坑
aggregation-rules.conf中的表达式配置:
test.<app>.all.<metrics>count (10) = sum test.<app>.ip*.<<metrics>>count
正确!
test.<app>.all.<metrics>count (10) = sum test.& ...
String Aggregation Techniques
String Aggregation Techniques
On occasion it is necessary to aggregate data from a number of rows into a single row, giving a list of data associated with a specific value. Using the SCOTT.EMP table a ...