Replace string value to integer value in NiFi within a same column

Question

I want to replace a \'string value\' and enter that value as an Integer Value using Nifi ReplaceText. I do not know how to achieve this in NiFi.

So my

Answer 1

Use QueryRecord processor and configure/enable Reader/Writer controller services

• Add custom sql query as new property to the processor

QueryRecord configs:

select Field1,Field2,
    CASE WHEN Field3='abc' THEN '0'
         WHEN Field3='pqr' THEN '1'
         WHEN Field3='lmn' THEN '2'
    end Field3,
        Field4,
    CASE WHEN Field5='John' THEN '10'
         WHEN Field5='Sam' THEN '20'
         WHEN Field5='Smith' THEN '30'
    end Field5 
from FLowfile

The output flowfile from QueryRecord processor will have your desired result

Field1,Field2,Field3,Field4,Field5
1,2,0,45,10
23,12,1,28,20
98,75,2,87,30

Use this template for your reference to the above flow and QueryRecord processor uses Apache Calcite sql parser.

Answer 2

What @Shu had suggested would work well but in case the number of lookups to be done is more or increasing, I would highly suggest to use the LookupRecord processor and configure it with a SimpleKeyValueLookupService for starters since your CASE statement would grow heavy and troublesome.

So your flow can be altered to something like

For a look on how to use, take a look at the simple template provided here : https://gist.github.com/zenfenan/37eb1e4cd0e59a63e85b0400040720b6

Useful links:

• https://community.hortonworks.com/articles/138632/data-flow-enrichment-with-nifi-lookuprecord-proces.html

• https://medium.com/@abdelkrim.hadjidj/data-flow-enrichment-with-apache-nifi-d221f1dde419