filtering

Filtering example

This example shows how to filter data with the WHERE clause in Dozer.

Let us write a query to calculate the tips and trip_miles for rides that cover more than 100 miles, along with an additional filter which ensures that the result will be for hvfhs_license_num ending with 03 only.

SQL Query and Structure

  SELECT tips, trip_miles
  INTO table1
  FROM trips 
  WHERE trip_miles > 100 
  AND hvfhs_license_num LIKE '%03';

Running

Dozer

To run Dozer navigate to the join folder /sql/filter & use the following command

dozer run

To remove the cache directory, use

dozer clean

Dozer Live

To run with Dozer live, replace run with live

dozer live

Dozer live automatically deletes the cache upon stopping the program.

Querying Dozer

Dozer API lets us use filter,limit,order_by and skip at the endpoints. For this example lets order the data in descending order of tips.

Execute the following commands over bash to get the results from REST and gRPC APIs.

REST

curl -X POST  http://localhost:8080/tip_amount/query \
--header 'Content-Type: application/json' \
--data-raw '{"$order_by": {"tips": "desc"}}'

gRPC

grpcurl -d '{"endpoint": "tip_amount", "query": "{\"$order_by\": {\"tips\": \"desc\"}}"}' \
-plaintext localhost:50051 \
dozer.common.CommonGrpcService/query