Arrays

Understand querying arrays in Kafka topic data with Lenses SQL Snapshot concepts engine for Apache Kafka

Create an array field

You can create array fields using the ..[] syntax:

CREATE TABLE table(
    _key INT,
    , fialdA INT[]            -- Simple array
    , fieldB.fieldC STRING[]) -- Array in a subfield
    , fieldD INT[][]          -- Nested array
FORMAT(avro, avro);

Select an array field

Tables can store data containing arrays. Here is a SQL statement for querying an array item:

SELECT
    fieldA[1]
     , fieldB.fieldC[2].x
FROM table
WHERE fieldA[1] LIKE '%Lenses%'

When working with arrays is good to check the array bounds. See the SIZEOF function in the list of supported functions.

Query for array size

Sometimes you want to find out how many items are in your array. To do so you can run:

SELECT
    SIZEOF(arrayFieldA)
FROM table