MAP

Represents map data in external tables in the Parquet, ORC, and Avro formats only. A MAP must use only primitive types and may not contain other complex types. You can use the MAP type in a table definition to consume columns in the data, but you cannot query those columns.

A superior alternative to MAP is ARRAY[ROW]. An array of rows can use all supported complex types and can be queried. This is the representation that INFER_TABLE_DDL suggests. For Avro data, the ROW must have fields named key and value.

Within a single table you must define all map columns using the same approach, MAP or ARRAY[ROW].

Syntax

In column definitions:

MAP<key,value>

Map input format for column definition

In a column definition in an external table, a MAP consists of a key-value pair, specified as types. The table in the following example defines a map of product IDs to names.

=> CREATE EXTERNAL TABLE store (storeID INT, inventory MAP<INT,VARCHAR(100)>)
    AS COPY FROM '...' PARQUET;