Tutorial by Examples: aggregati

We have a Student table with SubjectId. Here the requirement is to concatenate based on subjectId. All SQL Server versions create table #yourstudent (subjectid int, studentname varchar(10)) insert into #yourstudent (subjectid, studentname) values ( 1 ,'Mary' ) ,( 1 ,'John' ...

In case of SQL Server 2017 or vnext we can use in-built STRING_AGG for this aggregation. For same student table, create table #yourstudent (subjectid int, studentname varchar(10)) insert into #yourstudent (subjectid, studentname) values ( 1 ,'Mary' ) ,( 1 ,'John' ) ,( 1 ...

This is a single value metrics aggregation that calculates the average of the numeric values that are extracted from the aggregated documents. POST /index/_search? { "aggs" : { "avd_value" : { "avg" : { "field" : "name_of_field" } } ...

A single-value metrics aggregation that calculates an approximate count of distinct values. Values can be extracted either from specific fields in the document or generated by a script. POST /index/_search?size=0 { "aggs" : { "type_count" : { "ca...

A multi-value metrics aggregation that computes stats over numeric values extracted from the aggregated documents. These values can be extracted either from specific numeric fields in the documents, or be generated by a provided script. The extended_stats aggregations is an extended version of the ...

For this, we will use the function aggregate, which can be used as follows: aggregate(formula,function,data) The following code shows various ways of using the aggregate function. CODE: df = data.frame(group=c("Group 1","Group 1","Group 2","Group 2",&quo...

Aggregating with dplyr is easy! You can use the group_by() and the summarize() functions for this. Some examples are given below. CODE: # Aggregating with dplyr library(dplyr) df = data.frame(group=c("Group 1","Group 1","Group 2","Group 2","Group 2&...

Grouping with the data.table package is done using the syntax dt[i, j, by] Which can be read out loud as: "Take dt, subset rows using i, then calculate j, grouped by by." Within the dt statement, multiple calculations or groups should be put in a list. Since an alias for list() is .(), bo...