#Script Syntax

#Variable

In edql we can define variable to control the context logics, if we need to query multi indexes with the same query conditions, we can use variable as a Query DSL Block for these multiple actions, example:


function extractCodes() {
  POST my-index/_search
  {
    "size": 0,
    "aggs": {
      "t": {
        "terms": {
          "field": "title.keyword"
        }
      }
    }
  }
}
var p = jq(extractCodes(), "$.aggregations.t.buckets[*].key")
for (i in $p) {
  POST my-index/_search
  {
    "query": {
      "bool": {
        "must": [
          {
            "term": {
              "title.keyword": $i
            }
          }
        ]
      }
    },
  }
}

we define p variable for title keywords and extract it as array by jq, in for loop we iterate all keywords

#Function

Function is used to abstract the common logics and for building custom library for your own projects. such as data dictionary, common query logics for quickly query data and locate data issues.

#System Function

System Function is edql already defined functions for supporting file IO etc. example:

readJSON
```
local p = readJSON("filename")
```
read json file from file path
writeJSON
```
writeJSON($p, "filename")
```
write variable to file path
jq
```
jq({"name": "edql"}, "$.name")
```
used to extract json value as json type variable
TODO readExcel
TODO writeExcel

#Define Function

Define Function this is for user abstract common query logics, example:


function extractCodes() {
  POST my-index/_search
  {
    "size": 0,
    "aggs": {
      "t": {
        "terms": {
          "field": "title.keyword"
        }
      }
    }
  }
}

quickly aggregation current my index title keywords

#Import

import keyword is used to import other edql script as a library, we use this feature to design or create default functions. for import, there are two path could be used


import "library.edql"
import "https://raw.github.io/xxx"

#From Local File

EDQL will find import script by absolute path to load import file.

#From Github

EDQL will load import script from GitHub when using an HTTP url in import

#Iteration

EDQL supports an iterated collection by for loop, so in some times we want query results from a collection, it's easy to achieve this


for(a in [1, 2]) {
  echo a
}

#Comment

comment in edql script by using #


#mycomment