How to create External table with different collation in synapse

 We can’t create external tables with a different collation on the table level, collation is only applicable on the column level in the external tables.

See the below example reference.

USE [mydbname];
GO
CREATE EXTERNAL TABLE populationExternalTable
(
[country_code] VARCHAR (5) COLLATE Latin1_General_100_CI_AI_SC_UTF8,
[country_name] VARCHAR (100) COLLATE Latin1_General_100_CI_AI_SC_UTF8,
[year] smallint,
[population] bigint
)
WITH (
LOCATION = ‘csv/population/population.csv’,
DATA_SOURCE = sqlondemanddemo,
FILE_FORMAT = QuotedCSVWithHeaderFormat
);

See this microsoft official documenatation for more details on the external table syntax.