YAQL Tutorial

YAQL Introduction

What is YAQL?

YAQL means Yet Another Query Language, which is used to process and filter the data in data source like JSON, YAML etc.
YAQL can be embedded and also extensible query language.
YAQL query is similar like SQL query to search and operate on data.
YAQL query processor can be easily integrated in your code.
Queries are based on DSL's(Domain Specific Language), JSON, YAML and user inputs etc.
It's used to perform the complex queries against arbitrary objects.
Rich predefined functions and user defined functions are also possible in YAQL to extend.
YAQL has been developed in python.
YAQL is distributed through PyPi (Python Package index).
CLI tool and python module are two different ways to use the YAQL.

There are two different ways

//Using PyPi: 
pip install yaql

//Using system package manager: 
yum install python-yaql

Once installed YAQL on the machine, 'yaql' shell command can be used to get into the YAQL environment.

[machine]$ yaql

Once run yaql command, you will get YAQL environment as below,

yaql>

In yaql environment, null is returned if you run $ simply without loading any data in the environment.

yaql> $
null
yaql>

If you have input data as json format, use @load command is available in YAQL to load data in the environment.

yaql>@load input.json
Data from file input.json loaded into context

Once input data is loaded in the environment, $ can be used to access the input data.

yaql> $
{
    "name": "test", 
    "id": "1002"
}

To access name field in the input data,

yaql>$.name
test
yaql>